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Komatsu GX160K1-SKM-1(S/N 2087000-UP)

Maintenance schedule, common problems & OEM parts breakdown

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The Komatsu GX160K1-SKM-1 (S/N 2087000-UP) is the Honda-built gasoline engine fitted at the factory to the Komatsu PC01-1 and PC01-1A micro excavator, a sub-0.5t machine class built for digging in spaces too tight for a conventional mini excavator. The engine itself is a single-cylinder, air-cooled, carbureted 163cc unit rated around 2.6 kW (3.5 hp) at 3000 rpm, using recoil or electric starting and a mechanical centrifugal governor rather than any electronic engine controls. The host PC01-1/1A carries this engine in a compact chassis weighing roughly 380 kg (838 lb) with a 4.5 L fuel tank and about 4.8-4.9 L of hydraulic oil, and travels at roughly 1.4 km/h with a light ground pressure near 16.6 kPa. Komatsu produced the PC01 line in the mid-1990s as one of the smallest excavators it offered, and factory literature does not document an earlier PC01 generation that this model replaced.

Across its production run the GX160K1-SKM-1 saw no major redesign: it carries the same Honda GX160 architecture used broadly across Honda's industrial small-engine catalog, with the -SKM-1 designator marking Komatsu's specific carburetor jetting, governor setting, and mounting spec for the PC01 chassis rather than a unique engine casting. That commonality is what keeps this engine relevant in the parts market today: recoil starters, carburetors, ignition coils, and mufflers shared with the wider GX160 line remain easy to source and inexpensive, even though the PC01-1/1A host machine itself is long out of production and uncommon on the used market. Buyers looking at a GX160K1-SKM-1-powered unit today are usually after a rare ultra-compact micro excavator for tight-access utility, landscaping, or interior demolition work, or a donor engine pulled for its interchangeable Honda small-engine parts.

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.

Komatsu GX160K1-SKM-1(S/N 2087000-UP) specifications

Engine

ModelGX160K1-SKM-1 (Honda-built single-cylinder gasoline engine, Komatsu purchase-spec code), S/N 2087000-UP; fitted to the PC01-1/PC01-1A mini excavator
Type4-stroke, single-cylinder, air-cooled, OHV gasoline engine
Displacement163 cc (10.0 cu in)
Bore x stroke68 x 45 mm (base GX160 series dimension; not separately re-published for the SKM-1 governed variant)
Rated/gross power2.6 kW (3.5 hp) at 3000 rpm, governed output as installed in the excavator (base GX160 engine is rated higher, up to 3.6 kW/4.8 hp at 3600 rpm ungoverned; this unit runs at the lower governed setting for its application)
Cylinders1
Emissions tiernot documented for this engine/serial range - small industrial gasoline engine, predates modern off-road emissions tiering

Weights

Engine dry weightapprox. 15.1 kg (33 lb), base GX160-family figure; not separately confirmed for the SKM-1 governed variant - verify with your dealer
Host machine operating weight380 kg (837.8 lb), as installed in the Komatsu PC01-1/PC01-1A mini excavator
Ground pressure16.6 kPa (2.4 psi), host machine

Dimensions

Host machine shipping/transport length2.10 m (6.9 ft)
Host machine track width580 mm (1.91 ft)
Host machine track gauge450 mm (1.48 ft)
Host machine ground clearance100-120 mm (0.33-0.4 ft), varies by source
Host machine tail swing radius650 mm (2.14 ft)

Performance

Rated engine speed3000 rpm (governed)
Host machine max travel speed1.4-1.45 km/h (0.87-0.9 mph)
Hydraulic pump flow10.2 L/min (2.7 gpm), host machine
Hydraulic system relief pressure14.7 MPa (2130 psi), host machine
Swing speed7 rpm, host machine
Gradeabilitynot published for this model

Service capacities (summary)

Fuel tank4.5 L (1.2 gal), gasoline, host machine
Hydraulic system4.8-4.9 L (1.3 gal), host machine, varies by source
Engine oilapprox. 0.6 L, base GX160-family figure; not separately confirmed for the SKM-1 governed variant - verify with your dealer
Cooling systemair-cooled - no liquid coolant

Values vary by configuration, region, and serial range — confirm against your machine before planning transport or lifts.

GX160K1-SKM-1(S/N 2087000-UP) fluids & capacities

SystemCapacityRecommended fluid
Engine crankcase (oil)0.58 L (0.61 US qt)SAE 10W-30, API service class SJ or later, for general year-round use. SAE 5W-30 for cold-climate starting below 0°C (32°F). SAE 30 acceptable where ambient stays above 10°C (50°F). Splash-lubricated single-cylinder engine, no replaceable oil filter cartridge — oil level check via dipstick/level plug only.
Fuel tank3.6 L (0.95 US gal) per factory engine manual; some parts listings show 3.1 L (0.82 US gal) for this displacement class — treat as varies by tank configurationUnleaded automotive gasoline, pump (RON) octane 86 or higher. No leaded fuel. Fuel with up to 10% ethanol is acceptable; do not use E15/E85 blends.
Cooling systemNot applicableAir-cooled single-cylinder engine — no liquid coolant circuit, no coolant specification.
Transmission / final drives / hydraulic system / axlesNot applicable to this engine jobThese are host-machine (Komatsu PC01-1 / PC01-1A mini excavator chassis) systems, not part of the GX160K1-SKM-1 engine assembly's own fluid circuits. See the excavator OMM for hydraulic tank and travel/swing gear-case fluid specs.
Grease pointsNot documented for this engine in available sourcesNo factory-specified external grease points found for this small air-cooled engine assembly — verify with your dealer if the installed application (governor linkage, PTO, etc.) calls for periodic grease.

Capacities are refill values from factory literature — always fill to the dipstick/sight gauge, not the number.

Komatsu GX160K1-SKM-1(S/N 2087000-UP) maintenance schedule

Service intervalTasks
Every 50 h
  • Check engine oil level before each start and top up with SAE 10W-30 if below the fill mark.
  • Inspect the air cleaner element for dust clogging or damage; tap clean if lightly soiled.
  • Check for fuel, oil, and hydraulic leaks around the engine, pump, and cylinder rods.
  • Grease the boom, arm, and bucket pins.
  • Check hydraulic oil level at the sight gauge and top up as needed.
  • Change the break-in engine oil after the first 20 hours, then follow the 500-hour oil interval.
Every 250 h
  • Clean the sediment cup and in-line fuel strainer.
  • Clean and re-gap the spark plug; replace if the electrode is worn.
  • Wash the air cleaner element in warm soapy water and dry fully before refitting.
  • Check idle speed and governor linkage for smooth response; adjust if the engine hunts or surges.
  • Inspect tracks or track shoes for cracking, excess wear, or loose mounting bolts.
Every 500 h
  • Change engine oil and check drained oil for metal particles or varnish that signal internal wear.
  • Clean the spark arrester screen in the muffler.
  • Check hydraulic oil condition and top up; sample if the fluid looks dark or smells burnt.
  • Inspect cylinder rod seals on the boom, arm, and bucket for weeping.
  • Check track tension and adjust the idler.
Every 1,000 h
  • Check and adjust valve clearance: intake 0.15 mm, exhaust 0.20 mm.
  • Clean the fuel tank and carburetor bowl of varnish and sediment.
  • Inspect travel and swing reduction gear oil; top up or replace if discolored.
  • Replace the hydraulic return-line filter element.
  • Check the recoil starter rope and ignition coil for wear.
Every 2,000 h
  • Replace hydraulic oil (approximately 4.8-4.9 L) and clean the suction strainer.
  • Inspect the fuel line for hardening or cracking, common on machines that sit idle between jobs.
  • Overhaul the carburetor: float, needle valve, and gaskets.
  • Inspect the travel motor and swing bearing for internal wear.
  • Check cylinder bore and piston ring wear if compression is low, and decarbonize the combustion chamber.
Every 4,000 h
  • Replace all rubber hydraulic hoses regardless of visible condition given age-hardening risk on a machine this old.
  • Rebuild or replace the centrifugal governor and carburetor assembly if idle hunting persists after cleaning.
  • Inspect undercarriage rollers, idlers, and track links against service wear limits and rebuild as a set.
  • Pressure-test the hydraulic pump and cylinders; overhaul the gear pump if flow has dropped materially from new.

Servicing the GX160K1-SKM-1(S/N 2087000-UP) beyond the schedule

Predictive Maintenance & Fluid Analysis

This is a splash-lubricated single-cylinder gas engine with no ECM, so there is no fault-code diagnostics to lean on. Judge engine health by drained-oil appearance at each change (metal fines or dark varnish signal wear) and by exhaust color and idle steadiness as a stand-in for compression trending down. On the machine side, sample the small 4.8-4.9 L hydraulic reservoir at the 500-hour mark; because the circuit volume is tiny, dirt or water contamination shows up in cylinder and pump performance faster than on larger excavators.

Corrective & Common Repairs

Most GX160K1-SKM-1 units sit idle between jobs, so stale-fuel carburetor varnish (sticking float, clogged jets) and a worn or seized recoil starter rope are the most frequent fixes. Watch for centrifugal governor linkage wear causing rpm hunting or surging at idle. On the PC01-1/1A host, expect rod seal weep on the boom, arm, and bucket cylinders, and worn track shoes, rollers, or idlers on the compact undercarriage from years of light but unattended service.

Overhaul & Rebuild Points

Decades-old low-hour survivors commonly show piston ring stick and light cylinder bore wear from long dormancy rather than heavy use; check compression before assuming the bore needs boring. At major overhaul, decarbonize the combustion chamber and reseat or replace exhaust valves, since air-cooled unleaded-fuel operation accelerates seat recession. On the machine, rebuild the swing bearing, travel motor, and reduction gearboxes together, and bench-test the small gear-type hydraulic pump for flow loss before returning it to service.

Seasonal & Environment Servicing

Before winter storage, drain the carburetor float bowl and run the tank dry, since stale ethanol-blend fuel is the top cause of hard starting on a dormant single-cylinder engine. Choke and recoil-start mechanisms gum up fastest on units left idle over a season. In hot, dusty conditions clean the air cleaner and cooling fins more often than the standard interval, since the small air-cooled cylinder has limited cooling margin. Inspect rubber tracks for UV cracking or cold-weather hardening before each season change.

GX160K1-SKM-1(S/N 2087000-UP) common service parts

Part numberPart
HD17210ZE1822Element Ass'Y,Air CleanerCheck fitment →
HD17218ZE1821FilterCheck fitment →

Always confirm against your machine's serial number — cross-check any part in Heavy Parts AI before ordering.

GX160K1-SKM-1(S/N 2087000-UP) attachments & work tools

Ground-engaging work tools

This is a small general-purpose gasoline engine, not a machine with a boom or coupler. No buckets, breakers, grapples, or other ground-engaging work tools are offered for the engine itself.

Host-machine context

This engine variant is the factory powerplant supplied for the Komatsu PC01-1 / PC01-1A ultra-compact excavator line. Any bucket or work-tool options belong to that host machine's own attachment catalog, pin-mounted at the dipper, and are not part of the engine parts manual.

Starting system configuration

The wider GX-series small-engine family this unit belongs to is offered with recoil-start or electric-start configurations depending on suffix code. The exact factory start configuration built into this specific serial run is not confirmed in available documentation; verify against the engine parts manual or dealer.

Output shaft / mounting arrangement

Engines in this family use a horizontal, straight keyed output shaft (nominal 19 mm / 3/4 in diameter) for direct coupling to a pump, generator head, or driven equipment, rather than a PTO gearbox. Shaft length and keyway details can vary by application suffix.

Governor type

Standard governing on this engine family is a centrifugal mechanical governor. Some sibling suffix codes in the broader lineup offer an electronic governor for tighter speed regulation; which type shipped on this exact serial range is not confirmed.

Cooling package

Cooling is forced-air via a flywheel-driven fan and shrouding, standard across the family. No liquid-cooling or auxiliary cooling package option is documented for this engine.

Charging / accessory coil options

Some suffix variants in this engine family add an optional lighting or battery-charge coil for powering accessories or an electric starter battery. Coil output and availability for this specific SKM-1 serial range are not documented in available sources; treat as a dealer-verify item.

All GX160K1-SKM-1(S/N 2087000-UP) assemblies by section

Every catalogued assembly group for the Komatsu GX160K1-SKM-1(S/N 2087000-UP). Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.

Cylinder Block
Komatsu : Gx160k1-Skm-1(S/N 2087000-Up) : Cylinder Block : Camshaft And Rocker Arm
HD***00Lifter2
HD***10Plate,Guide1
HD***00Spring1
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Komatsu : Gx160k1-Skm-1(S/N 2087000-Up) : Cylinder Block : Crank Case Cover
HD***00Pipe,Oil Filler1
HD***40Pin2
HD***10Cap,Oil1
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Komatsu : Gx160k1-Skm-1(S/N 2087000-Up) : Cylinder Block : Crank Shaft
HD***00Gear,Timing1
HD***00Gear,Governor Drive1
HD***00Key1
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Komatsu : Gx160k1-Skm-1(S/N 2087000-Up) : Cylinder Block : Cylinder Block
HD***00Washer2
HD***00Pin1
HD***00Pin2
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Komatsu : Gx160k1-Skm-1(S/N 2087000-Up) : Cylinder Block : Flywheel? Cooling Fan And Cover
01***10Bolt - Relay And Flasher Mounting1
01***30Bolt,See Fig. K4010-17a01
01***05Nut,(For Air Conditioner Less), Nut1
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Komatsu : Gx160k1-Skm-1(S/N 2087000-Up) : Cylinder Block : Piston And Connecting Rod
HD***23Piston Ring Ass'Y1
HD***23Piston Ring Ass'Y1
HD***00Pin,Piston1
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Cylinder Head
Komatsu : Gx160k1-Skm-1(S/N 2087000-Up) : Cylinder Head : Air Cleaner And Connection
HD***21Filter1
HD***20Elbow Ass'Y1
HD***10Stud2
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Komatsu : Gx160k1-Skm-1(S/N 2087000-Up) : Cylinder Head : Cylinder Head
HD***00Cylinder Head Ass'Y1
HD***00Valve,Intake1
HD***00Retainer,Exhaust Valve1
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Komatsu : Gx160k1-Skm-1(S/N 2087000-Up) : Cylinder Head : Cylinder Head Cover
HD***00Cover,Head1
HD***00Clip2
HD***00Packing1
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Komatsu : Gx160k1-Skm-1(S/N 2087000-Up) : Cylinder Head : Muffler And Mounting
HD***00Protector,Inner1
HD***00Pipe,Exhaust1
HD***00Muffler1
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Electrical System
Komatsu : Gx160k1-Skm-1(S/N 2087000-Up) : Electrical System : Buzzer And Regulator
HD***10Regulator1
HD***00Suspension1
HD***03Buzzer Ass'Y1
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Komatsu : Gx160k1-Skm-1(S/N 2087000-Up) : Electrical System : Starting Motor
HD***23Starting Motor Ass'Y1
HD***13Motor Ass'Y1
HD***03Washer,Spring2
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Komatsu : Gx160k1-Skm-1(S/N 2087000-Up) : Electrical System : Starting Motor And Mounting
HD***00Pin2
HD***00Cover1
HD***03Screw1
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Fuel System
Komatsu : Gx160k1-Skm-1(S/N 2087000-Up) : Fuel System : Carburetor
HD***12Packing1
HD***05Screw Ass'Y1
HD***00Insulator1
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Komatsu : Gx160k1-Skm-1(S/N 2087000-Up) : Fuel System : Fuel Pump And Piping
HD***00Suspension1
HD***40Tube1
HD***83Fuel Pump Ass'Y1
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Komatsu : Gx160k1-Skm-1(S/N 2087000-Up) : Fuel System : Governor Arm Control And Carburetor Control
HD***10Bolt1
HD***50Rod,Choke1
HD***0HScrew1
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Komatsu : Gx160k1-Skm-1(S/N 2087000-Up) : Fuel System : Spark Plug And Ignishion Coil
HD***00Bolt1
HD***01Charge Coil Ass'Y1
HD***00Bolt2
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Frequently asked questions

What engine powers the Komatsu GX160K1-SKM-1 (S/N 2087000-UP)?

The GX160K1-SKM-1 is itself the engine: a Honda GX160 single-cylinder, air-cooled, carbureted gasoline engine of 163cc, rated around 2.6 kW (3.5 hp) at 3000 rpm, factory-fitted to the Komatsu PC01-1/PC01-1A micro excavator.

What is the operating weight of the machine this engine powers?

The host PC01-1/PC01-1A micro excavator has an operating weight of approximately 380 kg (838 lb), with a 4.5 L fuel tank and about 4.8-4.9 L of hydraulic oil capacity.

What replaced the GX160K1-SKM-1 / PC01-1A?

Komatsu does not document a direct, parts-interchangeable successor for this exact engine and serial break. Komatsu later introduced the PC01E-1, an electric micro excavator co-developed with Honda's eGX electrified power unit, which Komatsu describes as the electrified evolution of the PC01 conventional micro-excavator line, but it is a different powertrain rather than a direct replacement model.

What GX160K1-SKM-1(S/N 2087000-UP) owners discuss

Why won't the GX160K1-SKM-1 start, or why does it die a few seconds after starting?
Community consensus on the Honda GX160 gas engine that powers this micro excavator points almost always to the carburetor. A clogged jet, a stuck float, or a bowl vent gasket installed backward is the usual culprit when the engine fires briefly then dies. Ethanol-blended fuel left sitting over winter is the most common root cause: ethanol pulls varnish loose from the tank and fuel line and deposits it in the carburetor's small passages. Owners report the fix is a full carb clean (not just a jet blow-out) and switching to fresh, non-stale fuel with no more than 10% ethanol. If cleaning doesn't restore reliable starting, have your dealer verify the carburetor and fuel shutoff valve.
The engine surges or hunts at idle and under light load. What causes this on the GX160K1-SKM-1?
Small-engine owners describe this as a classic sign of a partially blocked idle or intermediate carburetor passage, or a governor linkage issue. The governor closes the throttle when RPM climbs too high, then reopens it once RPM drops, and a weak or misadjusted governor spring makes that cycle visible as surging. A dirty air filter is also frequently reported as a contributing factor, since it changes the air-fuel mixture enough to upset the governor's response. Work through air filter condition, governor spring/linkage, and carburetor cleanliness in that order before assuming a bigger problem.
Spark plugs keep fouling on this engine. What's the usual cause?
Forum consensus on the GX160 is that fouled plugs are almost always downstream of a dirty air filter or a carburetor running rich, not a bad plug itself. A clogged filter restricts airflow and richens the mixture even before it looks visibly dirty. Owners also report that a low-oil sensor malfunction can contribute to erratic running that accelerates fouling. Replace the filter, confirm the carburetor is set correctly, and only then replace the plug — swapping plugs alone rarely solves a recurring fouling pattern.
The engine shuts off unexpectedly while working on uneven ground or a slope. Is that normal?
Yes — this is a known trait of the GX160's low-oil sensor, which uses a float-type mechanism in the crankcase. On tilted or heavily sloped ground the oil can shift enough to trip the sensor even with an adequate oil level, killing ignition as a protective measure. This is by design, not a fault, though some owners on flatter worksites find it a nuisance. Because disabling the sensor removes a safeguard against running the engine low on oil, have your dealer verify oil level and sensor function before deciding how to handle it, rather than simply disconnecting it.
How does the recoil starter typically fail, and is it a DIY fix?
The recoil assembly is a common wear item on small Honda engines of this type. Reported failure modes are a broken pull rope (often right at the handle), a spring that loses tension over time, or pawls/tabs that stop engaging the starter cup so the rope pulls freely without turning the engine. Rethreading a broken rope is a workable field fix but can leave the spring under-tensioned unless it's fully rewound during reassembly; a full recoil assembly replacement is the more reliable repair. This is a straightforward mechanical task most owners handle themselves.
What should I check on the undercarriage and tracks before buying a used one of these micro excavators?
Because this class of machine is small and inexpensive relative to standard mini excavators, worn tracks, rollers, or a hooked/chipped sprocket can represent a disproportionately large share of the machine's value to repair. Run the tracks and look for uneven wear side-to-side, cracked or separated rubber track shoes, and slack that won't tension properly — all reported as the areas that most often decide whether a used unit is a bargain or a money pit. Also run the engine to full operating temperature and watch for smoke, hard starting, or oil weeping from the crankcase seal, since these machines saw long service lives before hitting the used market.
What should I inspect specifically on a used GX160K1-SKM-1 before buying?
Beyond the general undercarriage check, verify the engine starts cold without excessive choke work, idles without surging, and doesn't die when the machine is worked at an angle (see the low-oil-sensor note above — a machine that stalls on flat ground may indicate a genuinely low or contaminated oil level rather than just sensor sensitivity). Check the fuel system for varnish or gum if the machine sat idle for an extended period, and confirm the recoil starter pulls smoothly with proper rope rewind. Given the age of this engine and machine, budget for a carburetor rebuild and recoil service as routine reconditioning rather than red flags, and have your dealer verify hydraulic function and any structural wear on the boom and bucket linkage before purchase.

Compiled from owner and technician discussions across the industry — experiences vary by serial range and machine history.

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