Caterpillarengine - marinemarine engine
Caterpillar D343
Maintenance schedule, common problems & OEM parts breakdown
The Caterpillar D343 is a mechanical, non-electronic heavy-duty marine diesel engine dating from the 1960s: an inline six-cylinder design displacing 14.6 L (893 cu in) with a 137 x 165 mm (5.4 x 6.5 in) bore and stroke. Cat offered it in two factory configurations sharing the same block, bore, and stroke: the base turbocharged D343, rated around 238-245 bhp continuous, and the turbocharged-aftercooled D343TA, rated roughly 360-425 hp continuous with higher intermittent ratings reported in some field installations. As an engine rather than a mobile machine, the D343 has no operating weight in the usual sense; dry engine weight runs approximately 2,216-2,239 kg (4,885-4,935 lb) depending on configuration and accessories. Production ran through the 1960s into the late 1970s or early 1980s. The engine was most commonly paired with Twin Disc MG514-series marine reduction/reverse gears and found service in commercial fishing vessels, tugs, and other displacement-hull workboats, alongside industrial generator-set and pump-drive duty on the same block family.
The main split across the D343 line is aftercooling: the D343TA's intercooled charge air let Caterpillar raise continuous output well above the base turbocharged D343 while keeping the same 14.6 L architecture, so identifying which variant is on hand matters more than any mid-production running change. No factory-documented direct successor carries the D343 name forward; later Cat 3406-family marine diesels eventually covered a similar duty class, but that is not a confirmed factory replacement lineage. With production long ended and factory parts support thin, the D343 today survives mainly as a running workhorse in older commercial vessels and as a source of rebuildable long blocks, cylinder components, and marine-gear cores in the parts market. Engines with a documented service history and intact cooling and fuel systems command a premium, reflecting this engine's field reputation for surviving decades of continuous hard use when maintained on schedule.
Below: full specifications, fluids & capacities, the factory service schedule, common service parts, verified fault codes, what owners discuss, attachment guidance, the complete assembly directory, and a serial-number reference. Complete parts lists with full OEM part numbers, exploded diagrams, quantities, and fitment data are available free in Heavy Parts AI.
Caterpillar D343 specifications
Engine
| Model / configuration | D343, inline 6-cylinder, 4-stroke diesel. Offered as turbocharged (D343) and turbocharged-aftercooled (D343TA). |
| Displacement | 14.6 L (893 cu in) |
| Bore x stroke | 137 mm x 165 mm (5.4 x 6.5 in) |
| Power, turbocharged (base) | 177 kW (238 bhp) at the shaft / 183 kW (245 bhp) at the flywheel, continuous at 1800 rpm |
| Power, turbocharged-aftercooled (D343TA) | 268-276 kW (359-370 bhp) continuous at 1800 rpm; intermittent/maximum rating up to roughly 343-410 kW (460-550 bhp) depending on duty cycle |
| Generator-set rating (example) | 175 kW (210 kVA) continuous electrical output at 1800 rpm, engine-driven radiator cooling |
| Marine propulsion rating (as installed) | Ratings vary by gear/prop match; one factory-configured marine unit is rated up to 317 kW (425 hp). Consult the specific propulsion curve for a given boat/gear combination. |
| Emissions tier | Not applicable - pre-emissions-regulation design (1960s-era mechanical diesel, no ECM) |
Weights
| Dry weight, base engine | approx. 2,216 kg (4,885 lb), excluding marine gear and heat exchanger |
| Dry weight, D343TA (aftercooled) | approx. 2,239 kg (4,935 lb), roughly 23 kg (50 lb) heavier than the base engine |
| Shipping weight / ground pressure | Not published - stationary/marine power unit, not a mobile machine |
Dimensions
| Bare engine length x width x height | 1,938 mm x 813 mm x 1,262 mm (76.3 x 32 x 49.7 in), excluding protrusions |
| Complete marine propulsion package (with reverse/reduction gear and heat exchanger) | approx. 2,210 mm x 1,295 mm x 1,549 mm (87 x 51 x 61 in) - varies by gear and cooling package fitted |
Performance
| Idle speed | 550 rpm |
| Rated speed range | 1,800-2,100 rpm depending on power rating and variant |
| Governed/high-idle speed | approx. 2,000 rpm |
| Fuel consumption, turbocharged (base) | approx. 52 L/hr (13.8 US gal/hr) at 1,800 rpm rated load |
| Fuel consumption, D343TA (aftercooled) | approx. 73 L/hr (19.3 US gal/hr) at 1,800 rpm rated load |
| Field fuel burn (marine, reported) | approx. 57-76 L/hr (15-20 US gal/hr), varies by load and installation |
| Recommended marine reverse/reduction gear | 5-speed marine gear, forward and reverse, ratios from 2:1 to 6:1 depending on application |
Service capacities (summary)
| Engine oil | approx. 38 L (10 US gal); use Cat DEO or equivalent, SAE 30 or SAE 40 per ambient/service temperature |
| Cooling system | approx. 68 L (17.5 US gal) |
| Fuel tank | Not applicable - engine has no integral fuel tank; supplied from the host vessel or installation's tank |
Values vary by configuration, region, and serial range — confirm against your machine before planning transport or lifts.
D343 fluids & capacities
| System | Capacity | Recommended fluid |
|---|---|---|
| Engine crankcase (with filter) | 38-45 L (10-12 US gal) — sump/configuration dependent, confirm against the exact serial-prefix OMM | Cat DEO-spec diesel engine oil. Period guidance for this engine calls for straight SAE 30 in normal/warm ambient conditions, with SAE 40 accepted in sustained hot climates; drop to a lighter straight grade in sub-freezing starts. Confirm exact viscosity break points against the OMM for the specific serial range, since this is a mechanical (non-ECM) engine with no single universal multigrade call-out. |
| Cooling system | approx. 68 L (17.5 US gal) — figure is thin/single-sourced, verify against the OMM for the exact serial prefix and heat-exchanger vs radiator configuration | Cat heavy-duty coolant/antifreeze, glycol-based with corrosion/rust inhibitor, mixed per climate for the closed (fresh-water) circuit. Raw-water-cooled side draws sea or lake water and carries no coolant charge. |
| Fuel tank | Not specified in the engine documentation — the fuel tank is vessel-supplied and sized by the boat builder, not fixed by the engine OMM | No. 2-D diesel fuel meeting Cat's diesel fuel specification; use a winter-blend or treated fuel in cold ambient conditions. |
| Grease (chassis/accessory points) | Spec only — quantity not documented for this engine | NLGI 2 multipurpose grease (lithium-complex base) for accessory-drive, linkage, and raw-water pump grease points where fitted. |
Capacities are refill values from factory literature — always fill to the dipstick/sight gauge, not the number.
Caterpillar D343 maintenance schedule
| Service interval | Tasks |
|---|---|
| Every 10 h |
|
| Every 250 h |
|
| Every 500 h |
|
| Every 1,000 h |
|
| Every 2,000 h |
|
| Every 6,000 h |
|
Servicing the D343 beyond the schedule
Predictive Maintenance & Fluid Analysis
Run scheduled oil sampling on the D343's mechanical lubrication system to trend wear metals and catch bearing or liner wear before it causes a failure, since this engine has no ECM to flag faults electronically. Track raw water flow and heat exchanger temperature differential to catch scale buildup or a failing raw water pump impeller early. On the D343TA, monitor turbocharger boost and exhaust temperature spread across cylinders; a widening spread signals injector wear or valve trouble well before it forces a shutdown.
Corrective & Common Repairs
Raw water pump impellers and fuel filter/water separators are the most frequent D343 repairs given sustained marine duty cycles. Sooty startup smoke and rough idle usually trace to worn injectors or slipped injection timing on this mechanical fuel system, not electronics. Heat exchanger tube bundles foul with raw-water scale and need periodic cleaning or replacement. Governor linkage wear causes hunting at idle; inspect and re-pin worn linkage points before condemning the governor itself.
Overhaul & Rebuild Points
Cylinder liners, main and rod bearings, and valve seats are the core wear items on a high-hour D343 long block. On D343TA units, turbocharger bearings and the thrust collar wear faster than on the base D343 because of sustained boost pressure. Fuel injection pumps and nozzles typically need bench calibration or exchange at overhaul time. Because the fuel and governor systems are fully mechanical, plan a full injection-system rebuild alongside any inframe or major overhaul rather than deferring it.
Seasonal & Environment Servicing
Marine D343 installations need raw-water-side winterization: drain or antifreeze-protect the heat exchanger, aftercooler on D343TA units, and exhaust elbow ahead of freeze risk. Check zinc anodes each season in the heat exchanger and aftercooler, since salt or brackish water accelerates their consumption. Inspect the raw water strainer and sea strainer before the first start of each season. In warm, silty, or debris-heavy water, shorten impeller and strainer inspection intervals from the standard schedule.
D343 common service parts
| Part number | Part | Notes | |
|---|---|---|---|
| 4L-4604 | Fuel Filter | Fuel system service | Check fitment → |
| 1S-9547 | Transfer | Lubrication service | Check fitment → |
| 2N-3341 | Filter High Pressure | Scheduled service item | Check fitment → |
Always confirm against your machine's serial number — cross-check any part in Heavy Parts AI before ordering.
D343 fault codes & troubleshooting
| Code | Meaning | Likely cause | What to do |
|---|---|---|---|
| Low Oil Pressure Shutdown | Oil pressure contactor switch has tripped and energized the fuel-rack shutoff solenoid, stopping the engine. | Low oil level, worn oil pump, plugged filter, or a failed pressure switch/sender. | Do not restart until oil level and actual pressure are confirmed normal; check the switch and wiring if the gauge reads fine. |
| High Water Temperature Shutdown | Thermal-expansion sending element trips a micro-switch that energizes the shutoff solenoid, cutting fuel and stopping the engine. | Low coolant, blocked raw-water strainer or heat exchanger, failed thermostat, or a raw-water pump fault. | Let the engine cool, verify coolant level and raw-water flow, clear the strainer/heat exchanger before restart. |
| Overspeed Shutdown | Overspeed contactor trips when engine speed exceeds roughly 18 percent above governed full-load speed; the governor shutoff lever moves the fuel rack to cutoff. | Governor linkage fault, sticking fuel rack, or sudden loss of load such as a propeller coming out of the water. | Inspect governor linkage and rack movement, verify the overspeed trip point per the service manual before returning to service. |
| Low Oil Pressure Alarm (pre-shutdown warning) | Panel buzzer/light warns that oil pressure has dropped toward the shutdown threshold before the contactor switch actually trips. | Same causes as the shutdown condition, caught earlier: low oil level, pump wear, or a marginal sender. | Reduce load and idle down immediately, check oil level and gauge reading, do not ignore the warning stage. |
| High Water Temperature Alarm (pre-shutdown warning) | Panel buzzer/light warns of rising coolant temperature before the shutdown contactor engages. | Same causes as the shutdown condition in an earlier stage: restricted raw-water flow, low coolant, fouled heat exchanger. | Back off load, check raw-water intake/strainer and coolant level right away. |
| Loss-of-Coolant / No-Sensing Condition | If coolant is fully lost the thermal sending element has nothing to sense, so the automatic high-temperature shutdown may not activate even as the engine overheats. | Cracked hose, failed water pump seal, or a coolant leak that empties the system. | Do not rely on the alarm alone; watch the temperature gauge directly and keep coolant level on the watch-keeping checklist. |
| Remote/Manual Shutdown | Manual emergency-stop switch energizes the same shutoff-solenoid circuit used by the automatic safety switches. | Operator-initiated stop, or a remote panel E-stop being engaged. | Confirm no automatic alarm is also active before resetting and restarting. |
Codes and remedies are general guidance for this model family — always confirm with diagnostic tooling and your dealer before major repairs.
D343 attachments & work tools
Marine transmission / marine gear pairing
Twin Disc MG514 series marine gear was the factory-matched transmission for the D343, offered in shallow-case ratios of 2:1 and 3:1 and deep-case ratios from 4:1 up to 6:1. Reduction ratio was selected per vessel and propeller to suit displacement or semi-displacement hulls.
PTO / auxiliary drive
Front-mounted power take-off provision let the D343 drive hydraulic pumps, bilge or fire pumps, or other deck auxiliaries independent of the main gear train. Flywheel and flywheel housing follow SAE No. 0 sizing for mating to the marine gear and PTO-driven equipment.
Cooling system arrangement
Offered with keel-cooled or heat-exchanger (raw-water) cooling packages as factory-standard options. Keel-cooled packages omit the auxiliary seawater pump and reject heat through the hull; heat-exchanger packages use a cupro-nickel tube bundle (sized for roughly 50C ambient air and 32C seawater) with a raw-water pump circulating seawater through the core.
Governor
Standard governor is a hydra-mechanical fuel-pressure type, paired with a gear-driven centrifugal jacket-water pump. No electronic governing was fitted on this generation of engine.
Genset vs propulsion arrangement
Built either as a propulsion package coupled to a marine gear for direct or reduction-drive propulsion, or as a marine generator-set package running at a fixed 1800 rpm. Marine genset field ratings vary roughly 175-350 kW depending on aftercooling, duty class, and voltage/frequency (commonly 208-460V, 60Hz) - varies by configuration.
Aspiration / power configuration
Offered as base turbocharged D343 (roughly 238-245 bhp at 1800 rpm) or turbocharged-aftercooled D343TA rated substantially higher, with continuous ratings reported around 360-425 hp and intermittent/maximum ratings up to roughly 460-550 bhp depending on source and duty class - varies by configuration. Aftercooler and raw-water aftercooler lines group configuration varied across serial ranges.
All D343 assemblies by section
Every catalogued assembly group for the Caterpillar D343. Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.
Attachments
3f9847 Tachometer Dual Drive Joint
| 3F***47 | Adapter As-Drive | 1 |
4l4720 Air Cleaner Assembly
| 4L***20 | Air Cleaner Group | 1 |
7l7413 Air Filter Indicator Group
| 7L***13 | Air Filter Indicator Group | 1 |
5l2130 Air Filter Indicator Group
| 5L***30 | Air Filter Indicator Group | 1 |
7l6784 Air Filter Indicator Group
| 7L***84 | Air Filter Indicator Group | 1 |
3l517 Air Motor
| 3L***17 | Air Motor | 1 |
3l580 Air Motor Assembly
| 3L***80 | Air Motor Assembly | 1 |
6l6789 Air Precleaner Group--Full View
| 6L***89 | Air Precleaner Group | 1 |
Air Starting Arrangements
| 4L***77 | Air Starting Motor Group; Air Starting Motor Group (15 H.P.) | 1 |
| 6L***09 | Fuel Priming Pump Group | 1 |
| 7L***49 | Air Starting Motor Group; Air Starting Motor Group (18 H.P.) | 1 |
4l5777 Air Starting Motor Group
| 4L***77 | Air Starting Motor Group; Air Starting Motor Group (15 H.P.) | 1 |
7l8249 Air Starting Motor Group--18 H.P.
| 7L***49 | Air Starting Motor Group; Air Starting Motor Group (18 H.P.) | 1 |
2n6397 Alternator Assembly--24 Volt, 35 Ampere
| 2N***97 | Alternator As; Alternator Assembly | 1 |
5l1243 Alternator Assembly--32 Volt, 60 Ampere
| 5L***43 | Alternator As | 1 |
6l4108 Alternator Group--32 Volt, 60 Ampere--Type 2
| 6L***08 | Alternator Group | 1 |
6l4108 Alternator Group--32 Volt, 60 Ampere--Type 1
| 6L***08 | Alternator Group | 1 |
7l5139 Alternator Group--32 Volt, 60 Ampere--Type 1
| 7L***39 | Alternator Group | 1 |
7l5139 Alternator Group--32 Volt, 60 Ampere--Type 2
| 7L***39 | Alternator Group | 1 |
2n8804 Alternator Group--24 Volt, 35 Ampere
| 2N***04 | Alternator Group | 1 |
4l5836 Auxiliary Drive Group--L.H.--Type 2
| 4L***36 | Auxiliary Drive Group | 1 |
4l5836 Auxiliary Drive Group--L.H.--Type 1
| 4L***36 | Auxiliary Drive Group | 1 |
4l5799 Auxiliary Drive Group--R.H.--1.135 : 1 Ratio
| 4L***99 | Auxiliary Drive Group | 1 |
5l8943 Auxiliary Drive Group--R.H.--1.176 : 1 Ratio--Type 1
| 5L***43 | Auxiliary Drive Group--R.H. | 1 |
5l8943 Auxiliary Drive Group--R.H.--1.176 : 1 Ratio--Type 2
| 5L***43 | Auxiliary Drive Group--R.H. | 1 |
3n1552 Auxiliary Engine Conversion Arrangement--Factory Installation
| 0S***82 | Bolt Cover To Housing | 2 |
| 0S***91 | Screw,Cap,Hexagon Bearing Retainer; Part Of Kit P/N 1w***82 | 3 |
| 0T***55 | Bolt; (3/8-16x4.25-In)(Location S) | 1 |
4l8748 Basic Starting Engine Arrangement
| 1M***39 | Starting Crank Group | 1 |
| 1M***32 | Engine Support Group | 1 |
| 2H***64 | Oil Pump Assembly | 1 |
5l6395 Basic Starting Engine Arrangement
| 1M***39 | Starting Crank Group | 1 |
| 1M***32 | Engine Support Group | 1 |
| 2H***64 | Oil Pump Assembly | 1 |
1h1342 Battery Group--32 Volt, 200 Ampere Hours
| 1H***42 | Battery Group | 1 |
2n1943 Battery Group--30 Volt, 172 Ampere Hours
| 2N***43 | Battery Group | 1 |
1l5662 Battery Group--32 Volt, 120 Ampere Hours
| 1L***62 | Battery Group | 1 |
1l5663 Battery Group--30 Volt, 170 Ampere Hours
| 1L***63 | Battery Group | 1 |
4l5809 Bilge Pump Group
| 4L***09 | Bilge Pump Group | 1 |
Camshaft And Governor
Camshaft And Governor (7m6088 N/S)
| 7M***88 | Camshaft And Governor | 1 |
7m6038 Carburetor Assembly
| 7M***38 | Carburetor Assembly | 1 |
4l4646 Carburetor Assembly
| 4L***46 | Carburetor Assembly | 1 |
8l3915 Centrifugal Pump Assembly--Raw Water
| 8L***15 | Centrifugal Pump Assembly | 1 |
4l3811 Clutch And Pinion Control Group
| 4L***11 | Clutch And Pinion Control Group | 1 |
2f8223 Clutch Assembly
| 2F***23 | Clutch As | 1 |
8b243 Clutch Assembly--Type 2
| 8B***43 | Clutch Assembly | 1 |
8b243 Clutch Assembly -- Type 1
| 8B***43 | Clutch Assembly | 1 |
4l4666 Clutch Group
| 4L***66 | Clutch Group | 1 |
Compression Release Control (4l5719 N/S)
| 4L***19 | Compression Release Control | 1 |
Connecting Rod And Piston (8f2738 N/S)--2 Required
| 8F***38 | Connecting Rod And Piston | 1 |
5l1890 Pneumatic Remote Control Groups--Pilot House
| 4L***41 | Regulator Group-Air Pressure; Regulator And Conditioner | 1 |
| 5L***90 | Control Group | 1 |
| 5L***11 | Valve Group-Air Control | 1 |
5l1889 Pneumatic Remote Control Groups--Pilot House
| 2L***73 | Valve Group-Air Control | 1 |
| 4L***41 | Regulator Group-Air Pressure; Regulator And Conditioner | 1 |
| 5L***89 | Control Group | 1 |
Crankshaft (9h6218 N/S)
| 9H***18 | Crankshaft | 1 |
Cylinder Block, Cylinder Head And Valve Mechanism (4l3852 N/S)--Part 1 Of 2
| 4L***52 | Cylinder Block, Cylinder Head And Valve Mechanism | 1 |
Cylinder Block, Cylinder Head And Valve Mechanism--Part 2 Of 2
Cylinder Block, Cylinder Head And Valve Mechanism--Part 1 Of 2
Cylinder Block, Cylinder Head And Valve Mechanism (4l3852 N/S)--Part 2 Of 2
| 4L***52 | Cylinder Block, Cylinder Head And Valve Mechanism | 1 |
5l6528 Cylinder Head Service Group--Field Installation
| 5L***28 | Cylinder Head Service Group | 1 |
4l1895 Drip Collector Group
| 4L***95 | Drip Collector Group | 1 |
1m5061 Tachometer Drive Group
| 1M***61 | Drive Group-Tachometer | 1 |
4l5789 Tachometer Drive Group
| 4L***89 | Drive Group-Tachometer | 1 |
5l7430 Dual Panel Group--Electrical Instruments--12 Volt
| 5L***30 | Dual Panel Group | 1 |
6l2103 Dual Panel Group--Electrical Instruments--24 Or 32 Volt
| 6L***03 | Dual Panel Group | 1 |
6l2102 Dual Panel Group--Electrical Instruments--12 Volt
| 6L***02 | Dual Panel Group | 1 |
5l9893 Dual Panel Group--Mechanical Instruments--12 Volt
| 5L***93 | Dual Panel Group | 1 |
6l2101 Dual Panel Group--Mechanical Instruments--12 Volt
| 6L***01 | Dual Panel Group | 1 |
5l7431 Dual Panel Group--Electrical Instruments--24 Or 32 Volt
| 5L***31 | Dual Panel Group | 1 |
6l4665 Motor Assembly--12 Volt
| 6L***65 | Electric Motor Assembly | 1 |
4m1320 Electric Starter Group--12 Volt
| 4M***20 | Electric Starter Group | 1 |
4l6197 Electric Starter Group--12 Volt--Type 1
| 4L***97 | Electric Starter Group | 1 |
7m7793 Electric Starter Group--12 Volt--Type 1
| 7M***93 | Electric Starter Group | 1 |
7m7793 Electric Starter Group--12 Volt--Type 2
| 7M***93 | Electric Starter Group | 1 |
4l6197 Electric Starter Group--12 Volt--Type 2
| 4L***97 | Electric Starter Group | 1 |
4l6723 Electric Starting Arrangements--32 Volt
| 4L***48 | Fuel Priming Pump Group | 1 |
| 4L***22 | Electric Starting Motor Group | 1 |
| 4L***23 | Electric Starting Arrangements | 1 |
6l1704 Electric Starting Arrangements--32 Volt
| 4L***22 | Electric Starting Motor Group | 1 |
| 6L***04 | Electric Starting Arrangements | 1 |
| 6L***09 | Fuel Priming Pump Group | 1 |
1l6448 Electric Starting Group--12 Volt
| 1L***48 | Electric Starting Group | 1 |
6l5978 Electric Starting Group--12 Volt
| 6L***78 | Electric Starting Group | 1 |
8l8204 Electric Starting Motor Assembly--32 Volt--Part 1 Of 2
| 8L***04 | Electric Starting Motor Assembly | 1 |
8l8204 Electric Starting Motor Assembly--32 Volt--Part 2 Of 2
| 8L***04 | Electric Starting Motor Assembly | 1 |
6l1619 Motor Assembly--12 Volt
| 6L***19 | Electric Starting Motor Assembly | 1 |
4l6722 Electric Starting Motor Group--32 Volt--Type 1
| 4L***22 | Electric Starting Motor Group | 1 |
4l6722 Electric Starting Motor Group--32 Volt--Type 2
| 4L***22 | Electric Starting Motor Group | 1 |
7l3085 Electric Tachometer Group--12 Volt
| 5L***32 | Connector-- "Y" Harness | 1 |
| 5L***34 | Tachometer Assembly --12 Volt | 2 |
| 5L***52 | Sending Unit Assembly 12 Or 24 Volt | 1 |
3l6651 Electric Tachometer Group
| 3L***51 | Electric Tachometer Group | 1 |
7l3086 Electric Tachometer Group--24 Volt
| 5L***32 | Connector-- "Y" Harness | 1 |
| 5L***45 | Tachometer Assembly 24 Volt Or 32 Volt | 2 |
| 5L***52 | Sending Unit Assembly 12 Or 24 Volt | 1 |
7l3083 Electric Tachometer Group--12 Volt
| 5L***34 | Tachometer Assembly --12 Volt | 1 |
| 5L***52 | Sending Unit Assembly 12 Or 24 Volt | 1 |
| 7L***83 | Electronic Tachometers; Electric Tachometer Group 12 Volt | 1 |
7l3084 Electric Tachometer Group--24 Volt
| 5L***45 | Tachometer Assembly 24 Volt Or 32 Volt | 1 |
| 5L***52 | Sending Unit Assembly 12 Or 24 Volt | 1 |
| 7L***84 | Electronic Tachometers; Electric Tachometer Group 24 Volt | 1 |
1m7132 Engine Support Group
| 1M***32 | Engine Support Group | 1 |
3n1880 Exciter And Regulator Assembly--Part 1 Of 2
| 3N***80 | Exciter And Regulator Assembly | 1 |
3n1880 Exciter And Regulator Assembly--Part 2 Of 2
| 3N***80 | Exciter And Regulator Assembly | 1 |
4l3614 Exhaust Fitting Group
| 4L***14 | Exhaust Fitting Group | 1 |
4l4650 Exhaust Lines, Carburetor And Flame Arrestor Group
| 4L***50 | Exhaust Lines, Carburetor And Flame Arrestor Group; Exhaust Lines, Carburetor And Flame Arrester Group | 1 |
5l6788 Exhaust Lines, Carburetor And Flame Arrestor Group
| 5L***88 | Exhaust Lines, Carburetor And Flame Arrestor Group | 1 |
5l5788 Exhaust Lines, Carburetor And Flame Arrestor Group
| 5L***88 | Exhaust Lines, Carburetor And Flame Arrestor Group; Exhaust Lines, Carburetor And Flame Arrester Group | 1 |
1l9108 Flexible Fuel Line Group
| 1L***08 | Flexible Fuel Lines | 1 |
5l1114 Clutch Assembly
| 5L***14 | Flywheel Clutch Assembly | 1 |
4l4714 Front Power Take-Off--1 : 1 Ratio--Type 1
| 4L***14 | Front Power Take-Off | 1 |
4l4713 Front Power Take-Off--2.8 : 1 Ratio--Type 1
| 4L***13 | Front Power Take-Off | 1 |
4l4713 Front Power Take-Off Group--2.8 : 1 Ratio--Type 2
| 4L***13 | Front Power Take-Off | 1 |
4l4714 Front Power Take-Off Group--1 : 1 Ratio--Type 2
| 4L***14 | Front Power Take-Off | 1 |
5l8846 Front Power Take-Off Group--1 : 1 Ratio--Type 2
| 5L***46 | Front Power Take-Off Group | 1 |
5l8846 Front Power Take-Off Group--1 : 1 Ratio -- Type 1
| 5L***46 | Front Power Take-Off Group | 1 |
3n1889 Front Support Group
| 3N***89 | Front Support Group | 1 |
6l1709 Fuel Priming Pump Group--Type 2
| 6L***09 | Fuel Priming Pump Group | 1 |
6l1709 Fuel Priming Pump Group--Type 1
| 6L***09 | Fuel Priming Pump Group | 1 |
4l6148 Fuel Priming Pump Group
| 4L***48 | Fuel Priming Pump Group | 1 |
5l5508 Fuel Ratio Control Group
| 5L***08 | Fuel Ratio Control Group | 1 |
2h7161 Fuel System Group
| 2H***61 | Fuel System Group | 1 |
2n3322 Air Filter Indicator Group
| 2N***22 | Gauge Group-Air Cleaner; Air Filter Indicator Group | 1 |
4l3853 General Gasoline Starting Engine Arrangement
| 2H***61 | Fuel System Group | 1 |
| 4H***59 | Hand Crank Assembly | 1 |
| 4L***53 | General Gasoline Starting Engine Arrangement | 1 |
5l6396 General Gasoline Starting Engine Arrangement
| 2H***61 | Fuel System Group | 1 |
| 4H***59 | Hand Crank Assembly | 1 |
| 4L***67 | Flywheel Assembly | 1 |
4l2113 Generator Assembly--24 Volt, 18 Ampere
| 4L***13 | Generator | 1 |
9f2569 Generator--32 Volt, 15 Ampere
| 9F***69 | Generator | 1 |
8l59 Generator Assembly--3 Phase--End View -- Part 2 Of 2
| 8L***59 | Generator Assembly | 1 |
8l60 Generator Assembly--3 Phase--Side View -- Part 1 Of 2
| 8L***60 | Generator Assembly | 1 |
5l5751 Generator Assembly--32 Volt--18 Ampere
| 5L***51 | Generator Assembly | 1 |
1s1420 Generator Assembly--12 Volt, 24 Ampere
| 1S***20 | Generator Assembly | 1 |
8l60 Generator Assembly--3 Phase--End View -- Part 2 Of 2
| 8L***60 | Generator Assembly | 1 |
7m2159 Generator Assembly--12 Volt, 24 Ampere
| 7M***59 | Generator Assembly | 1 |
8l59 Generator Assembly--3 Phase--Side View -- Part 1 Of 2
| 8L***59 | Generator Assembly | 1 |
4l4725 Generator Group--12 Volt--24 Ampere--Type 1
| 4L***25 | Generator Group | 1 |
4l4725 Generator Group--12 Volt--24 Ampere--Type 3
| 4L***25 | Generator Group | 1 |
7l2164 Generator Group--32 Volt, 18 Ampere
| 7L***64 | Generator Group | 1 |
4l4725 Generator Group--12 Volt--24 Ampere--Type 2
| 4L***25 | Generator Group | 1 |
4l4727 Generator Group--32 Volt, 15 Ampere - Type 1
| 4L***27 | Generator Group | 1 |
4l4725 Generator Group--12 Volt, 24 Ampere--Type 4
| 4L***25 | Generator Group | 1 |
6l9412 Generator Group--24 Volt, 18 Ampere
| 6L***12 | Generator Group | 1 |
4l4727 Generator Group--32 Volt, 15 Ampere--Type 2
| 4L***27 | Generator Group | 1 |
4l6716 Glow Plug Group--24 Volt--Type 4
| 4L***16 | Glow Plug Group | 1 |
4l6716 Glow Plug Group--24 Volt--Type 2
| 4L***16 | Glow Plug Group | 1 |
4l6716 Glow Plug Group--24 Volt--Type 1
| 4L***16 | Glow Plug Group | 1 |
4l6716 Glow Plug Group--24 Volt--Type 6
| 4L***16 | Glow Plug Group | 1 |
4l6716 Glow Plug Group--24 Volt--Type 3
| 4L***16 | Glow Plug Group | 1 |
6l6680 Glow Plug Group--32 Volt
| 6L***80 | Glow Plug Group | 1 |
4l6716 Glow Plug Group--24 Volt--Type 5
| 4L***16 | Glow Plug Group | 1 |
4l6715 Glow Plug Resistor Group--Type 2
| 4L***15 | Glow Plug Resistor Group | 1 |
4l6715 Glow Plug Resistor Group--Type 1
| 4L***15 | Glow Plug Resistor Group | 1 |
Governor Control Chart
3l8869 Governor Control Group--R.H.
| 3L***69 | Governor Control Group; Governor Control Group Between 72 & 73 | 1 |
5l2518 Governor Control Group--L.H.
| 5L***18 | Governor Control Group | 1 |
4l6811 Lever Group
| 4L***11 | Governor Control Lever Group; Governor Control Lever Group Shown Below | 1 |
4l6804 Governor Control Mounting Group--L.H.
| 4L***04 | Governor Control Mounting Group | 1 |
3l6950 Governor Conversion Group
| 3L***50 | Governor Conversion Group | 1 |
2l6745 Governor Actuator Group--Pneumatic
| 2L***45 | Governor Pneumatic Actuator Group | 1 |
4l7604 Handle Group
| 4L***04 | Handle Group-Control; Governor Control Handle Group | 1 |
6l4035 Hardware Group
| 6L***35 | Hardware Group | 1 |
5l6442 Heat Exchanger Assembly
| 5L***42 | Heat Exchanger Assembly | 1 |
5l5975 Heat Exchanger Assembly
| 5L***75 | Heat Exchanger Assembly | 1 |
2r4840 Heat Exchanger Assembly
| 2R***40 | Heat Exchanger Assembly | 1 |
5l6443 Heat Exchanger Assembly
| 5L***43 | Heat Exchanger Assembly | 1 |
Heat Exchanger Chart
Hydraulic Starting System
| 2L***33 | Hydraulic Gauge | 1 |
| 2L***83 | Clamp Accumulator Clamp | 2 |
| 2L***84 | Support Accumulator Clamp | 1 |
4l4471 Ignition System Group--Type 2
| 4L***71 | Ignition System Group | 1 |
4l4471 Ignition System Group--Type 3
| 4L***71 | Ignition System Group | 1 |
4l4471 Ignition System Group
| 4L***71 | Ignition System Group | 1 |
4l4471 Ignition System Group--Type 1
| 4L***71 | Ignition System Group | 1 |
4l2150 Instrument Panel Group--Pilot House Mounted
| 4L***50 | Instrument Panel Group | 1 |
4l1687 Instrument Panel Group--Pilot House Mounted
| 4L***87 | Instrument Panel Group | 1 |
4l5761 Instrument Panel Group
| 4L***61 | Instrument Panel Group | 1 |
4l6152 Junction Box Group
| 4L***52 | Junction Box Group | 1 |
4l4984 Ether Starting Aid Kit
| 4L***84 | Kit-Starting Aid | 1 |
3n6668 Flexible Fuel Oil Lines Group
| 3N***68 | Lines Group-Flexible Fuel | 1 |
4l9581 Link Group
| 4L***81 | Link Group | 1 |
8m9145 Magneto Assembly
| 8M***45 | Magneto Assembly | 1 |
5m2850 Magneto Assembly
| 5M***50 | Magneto Assembly | 1 |
7m4700 Magneto Assembly
| 7M***00 | Magneto Assembly | 1 |
1s3350 Magneto Assembly
| 1S***50 | Magneto Assembly | 1 |
3s2987 Magneto Assembly
| 3S***87 | Magneto Assembly | 1 |
Mechanical Tachometer
| 5L***75 | Flexible Shaft-- 15 Foot; Flexible Shaft --15 Foot | 1 |
| 5L***64 | Drive Group-Tachometer | 1 |
| 5L***13 | Flexible Shaft-- 20 Foot | 1 |
8h1543 Motor Assembly--12 Volt
| 8H***43 | Motor Assembly | 1 |
7l8424 Motor Assembly
| 7L***24 | Motor Assembly | 1 |
5l5354 Electric Starting Motor--32 Volt--Part 1 Of 2
| 5L***54 | Motor Assembly--L.H. | 1 |
5l5354 Electric Starting Motor--32 Volt--Part 2 Of 2
| 5L***54 | Motor Assembly--L.H. | 1 |
7l4535 Tachometer Mounting Group
| 7L***35 | Mounting Group-Tachometer; Tachometer Mounting Group[[75 | 1 |
4l5792 Oil Level Gauge Group--L.H.
| 4L***92 | Oil Level Gauge Group | 1 |
2h7664 Oil Pump Assembly
| 2H***64 | Oil Pump Assembly | 1 |
2h7664 Oil Pump Assembly--Type 1
| 2H***64 | Oil Pump Assembly | 1 |
2h7664 Oil Pump Assembly--Type 2
| 2H***64 | Oil Pump Assembly | 1 |
4l3319 Oil Sump Pump Group--Type 1
| 4L***19 | Oil Sump Pump Group | 1 |
4l3319 Oil Sump Pump Group--Type 2
| 4L***19 | Oil Sump Pump Group | 1 |
5l1888 Pneumatic Remote Control Group--Engine Mounted--Type 1
| 5L***88 | Pneumatic Remote Control Group | 1 |
5l1888 Pneumatic Remote Control Group--Engine Mounted--Type 2
| 5L***88 | Pneumatic Remote Control Group | 1 |
5l8252 Power Take-Off Clutch Assembly
| 5L***52 | Power Take-Off Clutch Assembly | 1 |
2s5651 Precleaner Assembly
| 2S***51 | Precleaner As; -Air Cleaner | 1 |
5l4157 Precleaner Group--Full View--Type 1
| 5L***57 | Precleaner Group | 1 |
5l4157 Precleaner Group--Full View--Type 2
| 5L***57 | Precleaner Group | 1 |
4l5798 Auxiliary Drive Pulley Group
| 4L***98 | Pulley Group | 1 |
2s308 Fuel Priming Pump Assembly
| 2S***08 | Pump As-Fuel Priming | 1 |
4l8232 Pump--Type 2
| 4L***32 | Pump As-Fuel Priming; Fuel Priming Pump Assembly | 1 |
4l8232 Pump--Type.1
| 4L***32 | Pump As-Fuel Priming; Fuel Priming Pump Assembly | 1 |
6l5861 Bilge Pump Drive Group
| 6L***61 | Pump Drive Group | 1 |
5f3582 Centrifugal Pump
| 5F***82 | Pump Group; Centrifugal Pump | 1 |
6l5856 Bilge Pump Group
| 5J***82 | Pump | 1 |
| 6L***56 | Pump Group-Water | 1 |
| 8F***85 | Strainer As; Foot Valve And Strainer Assembly | 1 |
5l2065 Raw Water Aftercooler And Lines Group--Type 2
| 5L***65 | Raw Water Aftercooler And Lines Group | 1 |
5l2065 Raw Water Aftercooler And Lines Group - Type 1
| 5L***65 | Raw Water Aftercooler And Lines Group | 1 |
5l8946 Raw Water Pump And Drive Group--Type 1
| 5L***46 | Raw Water Pump And Drive Group | 1 |
5l8946 Raw Water Pump And Drive Group--Type 2
| 5L***46 | Raw Water Pump And Drive Group | 1 |
5l8947 Raw Water Pump And Lines Arrangement
| 4L***96 | Water Lines Group | 1 |
| 5L***46 | Raw Water Pump And Drive Group | 1 |
| 5L***47 | Raw Water Pump And Lines Arrangement | 1 |
4l5795 Raw Water Pump And Lines Arrangement
| 4L***95 | Raw Water Pump And Lines Arrangement | 1 |
| 4L***96 | Water Lines Group | 1 |
| 4L***00 | Sea Water Pump And Drive Group; Raw Water Pump And Drive Group | 1 |
3n1893 Rear Support Group
| 3N***93 | Rear Support Group | 1 |
3h2273 Regulator--32 Volt, 15 Ampere
| 3H***73 | Regulator | 1 |
6l5397 Regulator Assembly--32 Volt, 60 Ampere
| 6L***97 | Regulator As | 1 |
7m3963 Regulator Assembly--12 Volt, 24 Ampere
| 7M***63 | Regulator Assembly | 1 |
5l7691 Regulator Assembly--32 Volt, 15 Ampere
| 5L***91 | Regulator Assembly | 1 |
5l7690 Regulator Assembly--32 Volt, 18 Ampere
| 5L***90 | Regulator Assembly | 1 |
8h5877 Regulator--12 Volt, 24 Ampere
| 8H***77 | Regulator Assembly | 1 |
8m8809 Regulator Assembly--12 Volt, 24 Ampere
| 8M***09 | Regulator Assembly | 1 |
Relay And Element Assemblies
4l6190 Safety Alarm Contactor Group--Type 1
| 4L***90 | Safety Alarm Contactor Group | 1 |
4l6190 Safety Alarm Contactor Group--Type 2
| 4L***90 | Safety Alarm Contactor Group | 1 |
3l8876 Safety Drip Collector Group
| 3L***76 | Safety Drip Collector Group | 1 |
4l5800 Raw Water Pump And Drive Group
| 4L***00 | Sea Water Pump And Drive Group; Raw Water Pump And Drive Group | 1 |
4l3342 Service Meter Group
| 4L***42 | Service Meter Group | 1 |
5l4714 Servo Governor Conversion Group--Type 2
| 5L***14 | Servo Governor Conversion Group | 1 |
5l4714 Servo Governor Conversion Group
| 5L***14 | Servo Governor Conversion Group | 1 |
5l4714 Servo Governor Conversion Group--Type 1
| 5L***14 | Servo Governor Conversion Group | 1 |
6l2691 Stub Shaft Group--Front
| 6L***91 | Shaft Group-Stub | 1 |
5l7429 Single Panel Group--12 Volt
| 5L***29 | Single Panel Group | 1 |
5l9892 Single Panel Group--12 Volt
| 5L***92 | Single Panel Group | 1 |
5l7428 Single Panel Group--24 Or 32 Volt
| 5L***28 | Single Panel Group | 1 |
4l3817 Starter Pinion Group
| 4L***17 | Starter Pinion Group | 1 |
1m4639 Manual Starting Crank Group
| 1M***39 | Starting Crank Group | 1 |
8f4185 Foot Valve And Strainer Assembly
| 8F***85 | Strainer As; Foot Valve And Strainer Assembly | 1 |
6l2695 Stub Shaft Group--Rear
| 6L***95 | Stub Shaft Group | 1 |
5l8595 Solenoid Switch Assembly
| 5L***95 | Switch As-Solenoid | 1 |
4l2353 Electric Tachometer Group
| 4L***53 | Tachometer Group-Electric; Electric Tachometer Group | 1 |
1l5010 Air Receiver Group--10.5 Cubic Foot Capacity
| 1L***10 | Tank Group-Air | 1 |
7m8166 Turbocharger Assembly
| 7M***66 | Turbocharger Assembly | 1 |
7m8165 Turbocharger Assembly
| 7M***65 | Turbocharger Assembly | 1 |
7m8168 Turbocharger Assembly
| 7M***68 | Turbocharger Assembly | 1 |
7m8167 Turbocharger Assembly
| 7M***67 | Turbocharger Assembly | 1 |
8m4781 Turbocharger Assembly
| 8M***81 | Turbocharger Assembly | 1 |
9m6420 Turbocharger Assembly
| 9M***20 | Turbocharger Assembly | 1 |
8m1557 Turbocharger Assembly
| 8M***57 | Turbocharger Assembly | 1 |
5l6918 Turbocharger Oil Lines And Valve Group--Field Installation
| 5L***18 | Turbocharger Oil Lines And Valve Group | 1 |
4l4703 Upper Oil Filler Group
| 4L***03 | Upper Oil Filler Group | 1 |
2l1389 Trolling Valve Group
| 2L***89 | Valve Group | 1 |
1l5011 Regulator And Pressure Reducing Valve
| 1L***11 | Valve Group-Starting Air | 1 |
5l6925 Water Cooled Exhaust Elbow Group
| 5L***25 | Water Cooled Exhaust Elbow Group | 1 |
4l4664 Water Lines Group
| 4L***64 | Water Lines Group | 1 |
4l5796 Water Lines Group
| 4L***96 | Water Lines Group | 1 |
5l6390 Water Lines Group
| 5L***90 | Water Lines Group | 1 |
4l5788 Water Pump Assembly
| 4L***88 | Water Pump Assembly | 1 |
3l9921 Whistle Valve
| 3L***21 | Whistle Valve Assembly | 1 |
Diesel Engine
Aftercooler
Aftercooler (5l6418 N/S)
| 5L***18 | Aftercooler | 1 |
Air Cleaner (4l3328 N/S)--Dry Type
| 4L***28 | Air Cleaner | 1 |
Camshaft
Camshaft (4m298 N/S)
| 4M***98 | Camshaft | 1 |
Camshaft Drive (4m299 N/S)
| 4M***99 | Camshaft Drive | 1 |
Camshaft Drive (8m7138 N/S)
| 8M***38 | Camshaft Drive | 1 |
Connecting Rod And Piston (1m6946 N/S)--6 Required
| 1M***46 | Connecting Rod And Piston | 1 |
Connecting Rod And Piston (9m4178 N/S)--6 Required
| 9M***78 | Connecting Rod And Piston | 1 |
6l1563 Coupling Group--Field Installation
| 6L***63 | Coupling Group | 1 |
Crankshaft And Damper (4l2935 N/S)
| 4L***35 | Crankshaft And Damper | 1 |
Crankshaft Bearing Replacement Groups
9s7536 Crankshaft Replacement Gear Group--Field Installation
| 9S***36 | Crankshaft Replacement Gear Group | 1 |
Cylinder Block And Covers (4l3340 N/S)--End View--Part 2 Of 2
| 4L***40 | Cylinder Block And Covers | 1 |
Cylinder Block And Covers--End View--Part 2 Of 2
Cylinder Block And Covers--Side View--Part 1 Of 2
Cylinder Block And Covers (4l3340 N/S)--Side View--Part 1 Of 2
| 4L***40 | Cylinder Block And Covers | 1 |
Cylinder Block And Covers--Side View--Part 2 Of 2
4m2978 Cylinder Block Assembly
| 4M***78 | Cylinder Block As | 1 |
2s1803 Cylinder Block Assembly
| 2S***03 | Cylinder Block Assembly | 1 |
7m8650 Cylinder Block Assembly
| 7M***50 | Cylinder Block Assembly | 1 |
1s1440 Cylinder Block Assembly
| 1S***40 | Cylinder Block Assembly | 1 |
Cylinder Head And Valve Mechanism--End View--Part 2 Of 2
Cylinder Head And Valve Mechanism--End View-Part 2 Of 2
Cylinder Head And Valve Mechanism--Top View--Part 1 Of 2
Cylinder Head And Valve Mechanism--Top View-Part 1 Of 2
Cylinder Head And Valve Mechanism (5l6415 N/S)--End View--Part 2 Of 2
| 5L***15 | Cylinder Head And Valve Mechanism | 1 |
Cylinder Head And Valve Mechanism (5l6415 N/S)--Top View--Part 1 Of 2
| 5L***15 | Cylinder Head And Valve Mechanism | 1 |
Damper Guard
Oil Filler And Breather (4l3337 N/S)
| 4L***37 | Filler & Brth Group | 1 |
9m3223 Oil Filter Group
| 9M***23 | Filter Group-Engine Oil; Oil Filter Group | 1 |
Flywheel (4l3321 N/S)
| 4L***21 | Flywheel | 1 |
Fuel Filter (4l4604 N/S)
| 4L***04 | Fuel Filter | 1 |
Fuel Injection Valves And Lines (4l3349 N/S)
| 4L***49 | Fuel Injection Valves And Lines | 1 |
Fuel Pump And Accessory Drive Housing
Fuel Pump And Accessory Drive Housing (4l3344 N/S)
| 4L***44 | Fuel Pump And Accessory Drive Housing | 1 |
Fuel Pump Housing
Fuel Pump Housing (5l8858 N/S)
| 5L***58 | Fuel Pump Housing | 1 |
5m6488 Fuel Transfer Pump Group
| 5M***88 | Fuel Transfer Pump Group | 1 |
Gasket Kits
| 1S***23 | Gasoline Starting Engine Basic | 0 |
| 1S***18 | Gasoline Starting Engine Supplementary | 0 |
| 2P***62 | Diesel Engine Supplementary | 0 |
5l4091 Governor Group--Part 1 Of 2
| 5L***91 | Governor Group | 1 |
5l4091 Governor Group--Part 2 Of 2
| 5L***91 | Governor Group | 1 |
Lifting Eye (4l3320 N/S)
| 4L***20 | Lifting Eye | 1 |
4l5732 Marine Gear Oil Cooler Group
| 4L***32 | Marine Gear Oil Cooler Group | 1 |
6l1666 Marine Gear Oil Cooler Group
| 6L***66 | Marine Gear Oil Cooler Group | 1 |
4l3338 Oil Cooler Group
| 4L***38 | Oil Cooler Group | 1 |
6l1692 Oil Cooler Group
| 6L***92 | Oil Cooler Group; Engine Oil Cooler Group | 1 |
Oil Filler And Breather (6l2481 N/S)
| 6L***81 | Oil Filler And Breather | 1 |
Oil Filler And Breather (5l7815 N/S)
| 5L***15 | Oil Filler And Breather | 1 |
9m3202 Oil Filter Base Assembly
| 9M***02 | Oil Filter Base Assembly | 1 |
5h5795 Oil Filter Group
| 5H***95 | Oil Filter Group | 1 |
Oil Lines
Oil Lines (4l3345 N/S)
| 4L***45 | Oil Lines | 1 |
Oil Pan (4l3343 N/S)
| 4L***43 | Oil Pan; Oil Pan Group | 1 |
4m8026 Oil Pump Assembly
| 4M***26 | Oil Pump Assembly | 1 |
4l3347 Water Pump And Drive Group
| 4L***47 | Pump Group-Water | 1 |
Surge Tank And Water Lines (5l6417 N/S)--L.H.--Side View--Part 1 Of 2
| 5L***17 | Surge Tank And Water Lines | 1 |
Surge Tank And Water Lines (4l3334 N/S)--Front View-Part 2 Of 2
| 4L***34 | Surge Tank And Water Lines | 1 |
Surge Tank And Water Lines (4l3334 N/S)--L.H.--Side View-Part 1 Of 2
| 4L***34 | Surge Tank And Water Lines | 1 |
Surge Tank And Water Lines (5l6417 N/S)--Front View - Part 2 Of 2
| 5L***17 | Surge Tank And Water Lines | 1 |
Surge Tank And Water Lines--L.H. Side View--Part 1 Of 2
Surge Tank And Water Lines--Front View--Part 2 Of 2
7m8169 Turbocharger Assembly
| 7M***69 | Turbocharger Assembly | 1 |
2m8557 Turbocharger Assembly
| 2M***57 | Turbocharger Assembly | 1 |
Water Cooled Exhaust Manifold
Water Cooled Exhaust Manifold (4l3331 N/S)
| 4L***31 | Water Cooled Exhaust Manifold | 1 |
Marine Gears
7l5950 Flywheel Housing Adapter Group
| 3B***08 | Lockwasher Handrails To Dash | 16 |
| 7B***35 | Bolt, Bolt,Machine Grab Iron Mounting Applicable W/O Rops | 16 |
| 7L***50 | Flywheel Housing Adapter Group | 1 |
3n4168 Forward Shaft Group
| 3N***68 | Forward Shaft Group | 1 |
5l6099 Generator Drive Coupling Group
| 5L***99 | Generator Drive Coupling Group | 1 |
3n3456 Generator Installation Arrangement
| 0S***70 | Cap Screw (5/8" Long) | 8 |
| 0S***85 | Bolt; 12.7 mm (1/2") Diameter X 38.1 mm (1 1/2") Length Generator To Engine | 16 |
| 0T***68 | Bolt,Machine; Tube Mounting And Tube To Junction Block Uoc:Bsv,Bsx | 1 |
3n1700 Generator Installation Arrangement
| 0S***70 | Cap Screw (5/8" Long) | 8 |
| 0S***85 | Bolt; 12.7 mm (1/2") Diameter X 38.1 mm (1 1/2") Length Generator To Engine | 16 |
| 1B***01 | Nut Generator Line Leads; Nut-Generator Line Leads | 8 |
8f9866 Grease Gun
| 8F***66 | Grease Gun As | 1 |
Marine Control
| 5L***91 | Twin "S" Control --Pilot House; Twin "S" Control-- Pilot House | 1 |
| 5L***16 | Cable-16 Foot | 0 |
| 5L***17 | Cable-14 Foot | 0 |
5l7658 Marine Control Arrangement--Single Lever--R.H.
| 3L***87 | Control Group--Remotely Mounted | 1 |
| 3L***01 | Terminal Block-- Strut To Conduit | 2 |
| 4L***11 | Control Unit-- Single Lever-- Remote Station | 1 |
5l5949 Marine Gear
| 3N***45 | Transmission Group-Marine; Marine Gear Arrangement | 1 |
| 4L***37 | Mounting Group | 1 |
| 5L***83 | Marine Gear Assembly | 1 |
5l5950 Marine Gear
| 3N***47 | Transmission Group-Marine; Marine Gear Arrangement | 1 |
| 4L***37 | Mounting Group | 1 |
| 5L***82 | Marine Gear Assembly | 1 |
6l7167 Marine Gear Arrangement--3.50 : 1 Ratio
| 3N***48 | Transmission Group-Marine | 1 |
| 4L***37 | Mounting Group | 1 |
| 6L***02 | Marine Gear Assembly | 1 |
5l3967 Marine Gear Arrangement--6 : 1 Ratio
| 3N***53 | Transmission Group-Marine | 1 |
| 5L***67 | Marine Gear Arrangement | 1 |
| 5L***68 | Marine Gear Assembly | 1 |
5l3969 Marine Gear Arrangement--4.5 : 1 Ratio
| 3N***51 | Transmission Group-Marine | 1 |
| 5L***69 | Marine Gear Arrangement | 1 |
| 5L***70 | Marine Gear Assembly | 1 |
4l6241 Marine Gear Arrangement--2 : 1 Ratio
| 4L***37 | Mounting Group | 1 |
| 4L***41 | Marine Gear Arrangement | 1 |
| 5L***10 | Marine Gear Assembly | 1 |
4l6242 Marine Gear Arrangement--3 : 1 Ratio
| 4L***37 | Mounting Group | 1 |
| 4L***42 | Marine Gear Arrangement | 1 |
| 5L***11 | Marine Gear Assembly | 1 |
5l3968 Marine Gear Assembly--Part 3 Of 3--Type 1
| 5L***68 | Marine Gear Assembly | 1 |
5l5182 Marine Gear Assembly--3 : 1 Ratio--Part 2 Of 3--Type 2
| 5L***82 | Marine Gear Assembly | 1 |
5l3968 Marine Gear Assembly--Part 1 Of 3--Type 7
| 5L***68 | Marine Gear Assembly | 1 |
5l3968 Marine Gear Assembly--Part 2 Of 3--Type 1
| 5L***68 | Marine Gear Assembly | 1 |
5l3968 Marine Gear Assembly--Part 1 Of 3--Type 6
| 5L***68 | Marine Gear Assembly | 1 |
5l5182 Marine Gear Assembly--3 : 1 Ratio--Part 1 Of 3--Type 1
| 5L***82 | Marine Gear Assembly | 1 |
5l3968 Marine Gear Assembly--Part 2 Of 3--Type 4
| 5L***68 | Marine Gear Assembly | 1 |
5l5183 Marine Gear Assembly--2 : 1 Ratio--Part 1 Of 3--Type 3
| 5L***83 | Marine Gear Assembly | 1 |
6l4602 Marine Gear Assembly--Part 1 Of 3--Type 1
| 6L***02 | Marine Gear Assembly | 1 |
5l5182 Marine Gear Assembly--3 : 1 Ratio--Part 3 Of 3--Type 4
| 5L***82 | Marine Gear Assembly | 1 |
5l5183 Marine Gear Assembly--2 : 1 Ratio--Part 3 Of 3--Type 1
| 5L***83 | Marine Gear Assembly | 1 |
5l1111 Marine Gear Assembly--Part 3 Of 3--Type 1
| 5L***11 | Marine Gear Assembly | 1 |
6l4602 Marine Gear Assembly--3.50 : 1 Ratio--Part 2 Of 3--Type 3
| 6L***02 | Marine Gear Assembly | 1 |
6l4602 Marine Gear Assembly--3.50 : 1 Ratio--Part 3 Of 3--Type 2
| 6L***02 | Marine Gear Assembly | 1 |
5l1110 Marine Gear Assembly--Part 2 Of 3
| 5L***10 | Marine Gear Assembly | 1 |
5l1111 Marine Gear Assembly--3 : 1 Ratio--Part 2 Of 3--Type 2
| 5L***11 | Marine Gear Assembly | 1 |
5l3970 Marine Gear Assembly--Part 3 Of 3--Type 2
| 5L***70 | Marine Gear Assembly | 1 |
5l5183 Marine Gear Assembly--2 : 1 Ratio--Part 3 Of 3--Type 3
| 5L***83 | Marine Gear Assembly | 1 |
5l5182 Marine Gear Assembly--3 : 1 Ratio--Part 3 Of 3--Type 3
| 5L***82 | Marine Gear Assembly | 1 |
5l5183 Marine Gear Assembly--2 : 1 Ratio--Part 1 Of 3--Type 1
| 5L***83 | Marine Gear Assembly | 1 |
5l3970 Marine Gear Assembly--Part 3 Of 3--Type 4
| 5L***70 | Marine Gear Assembly | 1 |
5l3970 Marine Gear Assembly--Part 1 Of 3--Type 4
| 5L***70 | Marine Gear Assembly | 1 |
5l3970 Marine Gear Assembly--Part 2 Of 3 Type 2
| 5L***70 | Marine Gear Assembly | 1 |
5l5182 Marine Gear Assembly--3 : 1 Ratio--Part 3 Of 3-Type 1
| 5L***82 | Marine Gear Assembly | 1 |
5l3970 Marine Gear Assembly--Part 1 Of 3 Type 3
| 5L***70 | Marine Gear Assembly | 1 |
5l5183 Marine Gear Assembly--2 : 1 Ratio--Part 3 Of 3--Type 4
| 5L***83 | Marine Gear Assembly | 1 |
5l3968 Marine Gear Assembly--Part 2 Of 3--Type 7
| 5L***68 | Marine Gear Assembly | 1 |
5l3968 Marine Gear Assembly--Part 3 Of 3--Type 2
| 5L***68 | Marine Gear Assembly | 1 |
6l4602 Marine Gear Assembly--3.50 : 1 Ratio--Part 1 Of 3--Type 3
| 6L***02 | Marine Gear Assembly | 1 |
5l3970 Marine Gear Assembly--Part 1 Of 3--Type 5
| 5L***70 | Marine Gear Assembly | 1 |
5l5183 Marine Gear Assembly--2 : 1 Ratio--Part 1 Of 3--Type 2
| 5L***83 | Marine Gear Assembly | 1 |
6l4602 Marine Gear Assembly--3.50 : 1 Ratio--Part 2 Of 3--Type 2
| 6L***02 | Marine Gear Assembly | 1 |
5l3968 Marine Gear Assembly--Part 3 Of 3--Type 6
| 5L***68 | Marine Gear Assembly | 1 |
5l5182 Marine Gear Assembly--3 : 1 Ratio--Part 1 Of 3--Type 2
| 5L***82 | Marine Gear Assembly | 1 |
5l1110 Marine Gear Assembly--Part 1 Of 3
| 5L***10 | Marine Gear Assembly | 1 |
5l3968 Marine Gear Assembly--Part 2 Of 3--Type 3
| 5L***68 | Marine Gear Assembly | 1 |
5l1111 Marine Gear Assembly--Part 2 Of 3--Type 1
| 5L***11 | Marine Gear Assembly | 1 |
5l3968 Marine Gear Assembly--Part 1 Of 3--Type 5
| 5L***68 | Marine Gear Assembly | 1 |
5l5183 Marine Gear Assembly--2 : 1 Ratio--Part 3 Of 3--Type 2
| 5L***83 | Marine Gear Assembly | 1 |
5l5182 Marine Gear Assembly--3 : 1 Ratio--Part 2 Of 3--Type 4
| 5L***82 | Marine Gear Assembly | 1 |
5l3970 Marine Gear Assembly--Part 2 Of 3--Type 5
| 5L***70 | Marine Gear Assembly | 1 |
5l3968 Marine Gear Assembly--Part 1 Of 3--Type 4
| 5L***68 | Marine Gear Assembly | 1 |
5l3970 Marine Gear Assembly--Part 3 Of 3--Type 6
| 5L***70 | Marine Gear Assembly | 1 |
5l3970 Marine Gear Assembly--Part 2 Of 3
| 5L***70 | Marine Gear Assembly | 1 |
5l3968 Marine Gear Assembly--Part 2 Of 3--Type 6
| 5L***68 | Marine Gear Assembly | 1 |
5l5183 Marine Assembly--2 : 1 Ratio--Part 1 Of 3--Type 4
| 5L***83 | Marine Gear Assembly | 1 |
5l5182 Marine Gear Assembly--3 : 1 Ratio--Part 3 Of 3--Type 2
| 5L***82 | Marine Gear Assembly | 1 |
5l3970 Marine Gear Assembly--Part 2 Of 3--Type 4
| 5L***70 | Marine Gear Assembly | 1 |
5l3970 Marine Gear Assembly--Part 2 Of 3--Type 3
| 5L***70 | Marine Gear Assembly | 1 |
5l3968 Marine Gear Assembly--Part 1 Of 3--Type 1
| 5L***68 | Marine Gear Assembly | 1 |
5l1111 Marine Gear Assembly--3 : 1 Ratio--Part 1 Of 3--Type 2
| 5L***11 | Marine Gear Assembly | 1 |
6l4602 Marine Gear Assembly--3.50 : 1 Ratio--Part 3 Of 3--Type 3
| 6L***02 | Marine Gear Assembly | 1 |
5l5182 Marine Gear Assembly--3 : 1 Ratio--Part 2 Of 3--Type 3
| 5L***82 | Marine Gear Assembly | 1 |
5l3970 Marine Gear Assembly--Part 3 Of 3--Type 5
| 5L***70 | Marine Gear Assembly | 1 |
6l4602 Marine Gear Assembly--Part 2 Of 3--Type 1
| 6L***02 | Marine Gear Assembly | 1 |
5l3968 Marine Gear Assembly--Part 3 Of 3--Type 4
| 5L***68 | Marine Gear Assembly | 1 |
5l3968 Marine Gear Assembly--Part 3 Of 3--Type 3
| 5L***68 | Marine Gear Assembly | 1 |
5l3970 Marine Gear Assembly--Part 3 Of 3 Type 1
| 5L***70 | Marine Gear Assembly | 1 |
5l3970 Marine Gear Assembly--Part 1 Of 3--Type 6
| 5L***70 | Marine Gear Assembly | 1 |
5l3970 Marine Gear Assembly--Part 1 Of 3 Type 1
| 5L***70 | Marine Gear Assembly | 1 |
5l3970 Marine Gear Assembly--Part 3 Of 3--Type 3
| 5L***70 | Marine Gear Assembly | 1 |
5l3968 Marine Gear Assembly--Part 2 Of 3--Type 2
| 5L***68 | Marine Gear Assembly | 1 |
5l1110 Marine Gear Assembly--Part 3 Of 3
| 5L***10 | Marine Gear Assembly | 1 |
5l5183 Marine Gear Assembly--2 : 1 Ratio--Part 2 Of 3--Type 3
| 5L***83 | Marine Gear Assembly | 1 |
5l3968 Marine Gear Assembly--Part 1 Of 3--Type 2
| 5L***68 | Marine Gear Assembly | 1 |
5l5183 Marine Gear Assembly--2 : 1 Ratio--Part 2 Of 3--Type 4
| 5L***83 | Marine Gear Assembly | 1 |
5l3968 Marine Gear Assembly--Part 3 Of 3--Type 7
| 5L***68 | Marine Gear Assembly | 1 |
5l3968 Marine Gear Assembly--Part 2 Of 3--Type 5
| 5L***68 | Marine Gear Assembly | 1 |
5l1111 Marine Gear Assembly--3 : 1 Ratio--Part 3 Of 3--Type 2
| 5L***11 | Marine Gear Assembly | 1 |
5l3970 Marine Gear Assembly--Part 2 Of 3--Type 6
| 5L***70 | Marine Gear Assembly | 1 |
5l5183 Marine Gear Assembly--2 : 1 Ratio--Part 2 Of 3--Type 2
| 5L***83 | Marine Gear Assembly | 1 |
5l5182 Marine Gear Assembly--3 : 1 Ratio--Part 1 Of 3--Type 3
| 5L***82 | Marine Gear Assembly | 1 |
5l3968 Marine Gear Assembly--Part 3 Of 3--Type 5
| 5L***68 | Marine Gear Assembly | 1 |
5l5182 Marine Gear Assembly--3 : 1 Ratio--Part 2 Of 3--Type 1
| 5L***82 | Marine Gear Assembly | 1 |
5l3970 Marine Gear Assembly--Part 1 Of 3 Type 2
| 5L***70 | Marine Gear Assembly | 1 |
6l4602 Marine Gear Assembly--3.50 : 1 Ratio--Part 1 Of 3--Type 2
| 6L***02 | Marine Gear Assembly | 1 |
5l5182 Marine Gear Assembly--3 : 1 Ratio--Part 1 Of 3--Type 4
| 5L***82 | Marine Gear Assembly | 1 |
5l3968 Marine Gear Assembly--Part 1 Of 3--Type 3
| 5L***68 | Marine Gear Assembly | 1 |
6l4602 Marine Gear Assembly--Part 3 Of 3--Type 1
| 6L***02 | Marine Gear Assembly | 1 |
5l1111 Marine Gear Assembly--Part 1 Of 3-Type 1
| 5L***11 | Marine Gear Assembly | 1 |
5l5183 Marine Gear Assembly--2 : 1 Ratio--Part 2 Of 3--Type 1
| 5L***83 | Marine Gear Assembly | 1 |
7l7306 Mounting Group
| 7L***06 | Mounting Group | 1 |
4l6237 Mounting Group
| 4L***37 | Mounting Group | 1 |
7l7305 Mounting Group
| 7L***05 | Mounting Group | 1 |
5l3971 Mounting Group--Type 1
| 5L***71 | Mounting Group | 1 |
5l3971 Mounting Group--Type 2
| 5L***71 | Mounting Group | 1 |
Name Plates And Transfers
| 1H***40 | Transfer; Safety On Dash Or Guards When Used | 1 |
| 1M***98 | Transfer; Filter Instructions On Oil Filter Cover | 1 |
| 1S***47 | Transfer; Crankcase Instructions On Oil Filter Or Open Space Near Oil Filter | 1 |
2l1791 Oil Pump Assembly
| 2L***91 | Oil Pump Assembly | 1 |
5l5592 Pump Assembly
| 5L***92 | Oil Pump Assembly | 1 |
3n6094 Exciter And Modification Service Group
| 3N***94 | Resistor Group | 1 |
3n4214 Reverse Shaft Group
| 3N***14 | Reverse Shaft Group | 1 |
6l6357 Selector Valve Assembly
| 6L***57 | Selector Valve Assembly | 1 |
4l3222 Selector Valve Assembly
| 4L***22 | Selector Valve Assembly | 1 |
5l5593 Selector Valve Assembly
| 5L***93 | Selector Valve Assembly | 1 |
4l1560 Tool Group
| 4L***60 | Tool Group | 1 |
9s7977 Tool Group
| 9S***77 | Tool Group-Hand | 1 |
3n4553 Marine Gear Group--Part 2 Of 3
| 3N***53 | Transmission Group-Marine | 1 |
3n4551 Marine Gear Group--Part 1 Of 3
| 3N***51 | Transmission Group-Marine | 1 |
3n4547 Marine Gear Group--3 : 1 Ratio--Part 3 Of 3
| 3N***47 | Transmission Group-Marine; Marine Gear Arrangement | 1 |
3n4551 Marine Gear Group--Part 3 Of 3
| 3N***51 | Transmission Group-Marine | 1 |
3n4547 Marine Gear Group--3 : 1 Ratio--Part 1 Of 3
| 3N***47 | Transmission Group-Marine; Marine Gear Arrangement | 1 |
3n4547 Marine Gear Group--3 : 1 Ratio--Part 2 Of 3
| 3N***47 | Transmission Group-Marine; Marine Gear Arrangement | 1 |
3n4553 Marine Gear Group--Part 3 Of 3
| 3N***53 | Transmission Group-Marine | 1 |
3n4545 Marine Gear Group--2 : 1 Ratio--Part 1 Of 3
| 3N***45 | Transmission Group-Marine; Marine Gear Arrangement | 1 |
3n4553 Marine Gear Group--Part 1 Of 3
| 3N***53 | Transmission Group-Marine | 1 |
3n4548 Marine Gear Group--3.50 : 1 Ratio--Part 3 Of 3
| 3N***48 | Transmission Group-Marine | 1 |
3n4545 Marine Gear Group--2 : 1 Ratio--Part 3 Of 3
| 3N***45 | Transmission Group-Marine; Marine Gear Arrangement | 1 |
3n4551 Marine Gear Group--Part 2 Of 3
| 3N***51 | Transmission Group-Marine | 1 |
3n4548 Marine Gear Assembly--3.50 : 1 Ratio--Part 2 Of 3
| 3N***48 | Transmission Group-Marine | 1 |
3n4548 Marine Gear Assembly--3.50 : 1 Ratio--Part 1 Of 3
| 3N***48 | Transmission Group-Marine | 1 |
3n4545 Marine Gear Group--2 : 1 Ratio--Part 2 Of 3
| 3N***45 | Transmission Group-Marine; Marine Gear Arrangement | 1 |
7l7310 Selector Valve Assembly
| 7L***10 | Valve As-Selector | 1 |
D343 serial number reference
The serial plate for a D343 engine is riveted low on the side of the engine block, often near the starter motor; on marine installations it can also be tagged on the flywheel housing or injection-pump side of the block. The plate shows an 8-character serial number: a 3-character prefix (letters plus numbers) tying the unit to its specific engine build, followed by a 5-digit sequence number unique to that engine.
| Prefix | Identifies | Notes |
|---|---|---|
| 33B | D343 marine propulsion engine | Factory serial range for the D343 marine propulsion engine (service literature covers 33B00001 and up). Six-cylinder, 14.6 L (893 cu in), 137 x 165 mm bore/stroke. Marine units on record under this prefix run up to roughly 425 hp, which lines up with a turbocharged/aftercooled build rather than a naturally aspirated one. No confirmed production-year range. |
| 62B | D343 industrial engine | Factory serial range for the D343 industrial engine, documented alongside the 33B marine range in the same service manual (S/N 62B1 and up, 33B1 and up). Same base six-cylinder block; units on record under this prefix run up to roughly 430 hp, consistent with a turbocharged build. No confirmed production-year range. |
| 52K | D343 engine-machine (off-highway prime mover) | Serial range for a D343 engine-machine arrangement (service literature covers 52K00001 and up), tied to off-highway equipment installations such as scraper and wheel-loader applications rather than marine or generator-set duty. Confirm exact machine fitment with a dealer before ordering parts against this prefix. |
| 92B | D343 generator-set engine | Seen on a D343-powered diesel generator set rated around 175 kW continuous at 1800 rpm. That output band matches a standard turbocharged D343, not a naturally aspirated build. Documentation for this prefix is thin; confirm with a dealer before relying on it. |
Frequently asked questions
What engine is the Caterpillar D343?
The D343 is itself the engine: a mechanical, non-electronic inline six-cylinder diesel displacing 14.6 L (893 cu in) with a 137 x 165 mm bore and stroke. It was offered as the base turbocharged D343 (roughly 238-245 bhp continuous) and the turbocharged-aftercooled D343TA (roughly 360-425 hp continuous, varying by rating and configuration).
What is the operating weight of the Caterpillar D343?
The D343 is an engine, not mobile equipment, so it has no operating weight in the usual sense. Dry engine weight alone runs approximately 2,216-2,239 kg (4,885-4,935 lb) depending on configuration and accessories; add the marine gear for total installed package weight.
What replaced the Caterpillar D343?
No factory-documented direct successor carries the D343 name forward. Production ended in the late 1970s or early 1980s; later Cat 3406-family marine diesels eventually filled a similar duty class, but that is not a confirmed factory replacement lineage, so verify cross-reference details with a dealer for your specific application.
What D343 owners discuss
What configuration is the D343, and how does the D343TA differ from the base turbocharged D343?
The D343 is an inline 6-cylinder diesel with a 137 mm (5.4 in) bore and 165 mm stroke, displacing about 14.6-15 L. It is a mechanical, low-revving design carried over into the 3406 that replaced it. The base engine is offered turbocharged only; the D343TA adds an aftercooler behind the turbo, which lets the same block run higher boost for more continuous power without pushing exhaust and piston temperatures as hard. Low idle sits around 550 rpm with a governed top end near 2000 rpm on most builds - a slow-turning, torque-first engine rather than a high-revving one.
What horsepower and fuel burn do owners actually see out of these?
Ratings vary by configuration/series and by how the boat or genset was set up at the factory. Base turbocharged units are commonly quoted around 238-245 bhp at 1800 rpm continuous, burning roughly 13-14 US gal/hr (about 50-53 L/hr) at that rating. Marine propulsion installs with the TA package are reported anywhere from the mid-300s up to about 460 hp depending on duty cycle and gearing, so treat any single horsepower number as configuration-specific and confirm it against the engine's own rating plate rather than a magazine spec sheet.
How does this engine hold up long term - what do commercial operators report?
Reputation among tug and fishing-fleet operators is strong. Boats run hard for weeks at a time have had heads pulled annually as routine inspection, with cylinders coming up clean enough to bolt the same heads back on year after year, and engines with 20,000+ hours in service are not unusual. It was a mainstay in the Southeast Alaska seine fleet and in smaller tugs for exactly that reason - low stress per cylinder for the displacement. On the construction/industrial side (scraper and loader applications sharing the same block) mechanics describe it the same way: a genuinely good motor, just an expensive one to rebuild once parts and machine work are needed.
What wear items and mechanical quirks come up most in shop talk?
Exhaust valve and valve-guide wear is the recurring theme on this engine family - burnt valves and rising oil consumption are the classic tell that guides and seats are due. Because the D343 shares major components with its D346/D348/D349 siblings, a shop pulling heads on any of these is checking valve condition as a matter of course, not chasing a one-off defect. Beyond that, forum consensus is that failures tend to be wear-and-tear (rings, bearings, injectors going soft with hours) rather than a design-specific weak point - consistent with an over-built, low-stress industrial engine that was later detuned into shorter-lived reputations only when re-rated well past factory continuous power.
What do owners flag about the cooling system in raw-water and heat-exchanger installs?
The complaints mirror what shows up on every Cat marine engine of this era rather than anything unique to the D343: raw water pump impellers take the brunt of debris and cavitation damage and are the number one cause of a cooling-flow complaint, so seasonal or roughly 100-hour impeller inspection is treated as routine rather than optional. On the heat exchanger and oil cooler, saltwater-side scale buildup is the long-term threat - an annual raw-water-side flush with a descaling solution is commonly cited as cheap insurance, along with checking the sacrificial zinc anodes on the pump and exchanger housings each haul-out. Any sustained overheating on this engine warrants having your dealer or a qualified marine diesel shop verify the raw water pump, thermostat, and heat exchanger core condition before running it hard again.
Is the mechanical injection pump and governor on this engine trouble-prone?
Dedicated D343 threads on injection pump and governor behavior are thin, which is itself telling for an engine this old still in service - it is not a commonly reported failure point. The pump is a mechanical, gear-driven, inline-style unit typical of Caterpillar engines of this generation, and like its contemporaries it depends on periodic timing and rack calibration rather than being set-and-forget. If a D343 develops a rough idle, power fade under load, or hard restarts, have your dealer or an injection pump specialist check pump timing, governor linkage free play, and for air ingestion at the pump housing before assuming a bigger problem - these are adjustment and calibration items on a well-maintained example, not signs the pump is worn out.
What should a buyer check before purchasing a boat or genset running a used D343?
Owners consistently recommend going past the seller's paperwork: borescope the cylinders through the injector or valve ports to check for scoring or glazing, and pull a rod bearing cap or two as a spot check on lower-end wear before committing. Confirm the actual horsepower rating stamped on the tag matches what the boat is represented as running, since D343 and D343TA ratings span a wide range and a re-rated or over-fueled example changes the wear picture. Check maintenance records for head-off inspection history, look at raw water pump and heat exchanger service intervals, and inspect for salt-water corrosion around the block and cooling passages on any engine that has sat idle. Given the engine's age and the cost of a surprise rebuild, have your dealer or an independent marine diesel surveyor verify compression, oil analysis, and injection pump condition before finalizing a purchase.
Compiled from owner and technician discussions across the industry — experiences vary by serial range and machine history.
Serial-range & configuration variants
This page covers the Caterpillar D343. Related factory variants of the same model family:
D343D343
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