Home›Engines›Caterpillar OHV

Caterpillar OHV Engine

Name: Caterpillar OHV Engine
Brand: Caterpillar

The Caterpillar OHV is a 79.7 L ohv engine. It powers generator sets from Caterpillar, including the INV2000, RP3600 and RP5500.

Also known as: CAT OHV

79.7 L

Displacement

On this pageSpecs Generator sets FAQ Service intervals Torque & specs Fluids Procedures

Engine specifications

Displacement	79.7 L
Aspiration	OHV

Generator sets powered by this engine

Caterpillar INV2000 Caterpillar RP3600 Caterpillar RP5500

How to read your Caterpillar engine serial & model number →

Common problems

Engine Will Not Start
Cause: Generator switch in the off “0” position
Fix: Turn the generator switch to the correct position.
Engine Shuts Down
Cause: Out of fuel
Fix: Check the fuel. Fill the tank if necessary.
Engine Runs, But Generator Does Not Provide Power
Cause: Generator overloaded, overload light is on
Fix: Turn off and unplug all electrical devices, shut down the engine, wait 10-15 minutes and start the engine, connect fewer or lighter electrical loads.
Engine Runs Rough (with load)
Cause: Dirty air filter
Fix: Stop the engine and check the air filter. Clean if needed. Start the engine / check if it runs rough.
Engine Runs Rough (no load)
Cause: Dirty air filter
Fix: Stop the engine and check the air filter. Clean if needed. Start the engine / check if it runs rough.
Generator makes a 'spark knock' or 'pinging' noise
Cause: No fuel, Stale gasoline or water in gasoline
Fix: Drain fuel and carburetor. Refuel with fresh gasoline.
Engine Starts But Runs Rough or Does Not Have Enough Power
Cause: Dirty air filter, Generator inclined, Air in fuel line or fuel line clogged, Not enough fuel to the engine, Engine Smart Control switch on, Carbon built up in combustion chamber, Cylinder pressure, Inspect the cylinder head gasket, If the engine still has low power
Fix: Check the air filter. Clean or replace as needed., Move generator to a level position., Check the fuel line. Clear or replace needed., Make sure the needle valve is closing properly. Clean or replace as needed., Inspect the fuel nozzle. Clean if needed., Turn the Engine Smart Control switch off., Remove the cylinder head and clean if needed., Refer to the Maintenance Specifications chart for the proper value. Adjust or repair as needed., Replace if damaged., If the engine still has low power, Rebuild the engine, replace the engine, or consider replacing the unit.
Engine Overheating
Cause: Low Oil
Fix: Check the oil. Refill the oil or change the oil as needed., Start the engine and let it reach operating temperature. Check the temperature., If blocked, clear the blockage., Remove the debris., Inspect cylinder, piston, and piston rings. Replace if needed., Inspect connecting rod. Replace if worn.
Engine Making Unusual Sound
Cause: Knocking, Check for carbon deposits in the cylinder. Clean if needed., Check the piston and piston rings. If the piston or rings are worn or broken, replace the defective part., Inspect the piston pin and piston pin hole. Replace if worn.
Fix: Check the engine temperature. If the engine is running too hot, refer to the section on overheating. Start the engine. Check for unusual sound. Make sure the fuel is good and the proper rating. Drain and refill the fuel tank if necessary., Refer to the Maintenance Specifications chart for the proper value. Adjust or repair as needed., Clean if needed., If the engine still makes an unusual sound, Rebuild the engine, replace the engine, or consider replacing the unit.

Compiled from service & troubleshooting documentation across every generator set that uses the Caterpillar OHV.

Service intervals

Item	Action	Hours	Months	Notes
Engine Oil	Change	25 hr	3 mo	First service — First Service
Air Filter	Check	25 hr	3 mo	Every 25 Service Hours or 3 Months
Spark Arrester	Other	50 hr	3 mo	Inspect/Clean/Replace
Spark Arrestor	Clean	50 hr	3 mo	Every 50 Service Hours or 3 Months
Spark Plug	Inspect	100 hr	6 mo	Every 100 Service Hours or 6 Months
Spark Plug	Other	100 hr	6 mo	Inspect/Adjust/Replace
Cylinder Head	Clean	300 hr	12 mo	Every 300 Service Hours or 1 Year
Engine Valve Lash	Check	300 hr	12 mo	Every 300 Service Hours or 1 Year
Engine Oil Level	Check			First service — Before each start
Fuel Line	Check		24 mo	Every 2 Years
Fuel Line	Other		24 mo	Check/Replace if necessary
Generator	Inspect		1 mo	Every Month

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Service specifications

Type	Item	Value	Unit	Condition
Clearance	Cylinder bore I.D.	48.6	mm
Clearance	Exhaust valve clearance	0.05 ± 0.02	mm
Clearance	Intake valve clearance	0.05 ± 0.02	mm
Clearance	Piston to cylinder clearance	0.010 – 0.045	mm
Gap	Spark Plug Gap	0.7 - 0.8	mm
Gap	Spark plug gap	.024 - .028	inches (0.6-0.7mm)
Pressure	Compression (at 1400 rpm)	0.95 - 1.25	MPa	at 1400 rpm
Speed	Maximum speed (no load)	4650	rpm
Torque	Spark plug tightening torque	9 ± 2	lb ft (12.5 ± 2 Nm)

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Recommended fluids

Fluid	Grade	Standard	Ambient	Capacity	Notes
Engine oil	SAE 0W-40, SAE 5W-40, SAE 10W-30, SAE 15W-40			0.38 L	Multi-viscosity options per ambient temperature
Engine oil	SAE 0W-40		-40°C to 40°C	0.4 quart/L	Non-detergent and 2-stroke oils must not be used
Engine oil	SAE 5W-40		-30°C to 50°C	0.4 quart/L	Non-detergent and 2-stroke oils must not be used
Engine oil	SAE 10W-30		-18°C to 40°C	0.4 quart/L	Non-detergent and 2-stroke oils must not be used
Engine oil	SAE 15W-40		-10°C to 50°C	0.4 quart/L	Non-detergent and 2-stroke oils must not be used
Fuel		Unleaded		3.8 L	1 U.S. gallon fuel capacity
Fuel	Unleaded gasoline, octane ≥87, ≤10% ethanol			1.0 gal/L	Do not mix oil with gasoline; use fuel stabilizer for storage

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Procedures

Add oil maintenance

Tools: oil funnel

Add oil to level indicated
Use included oil funnel

Air Filter – Check maintenance

⚠ Never operate without air filter in place

Open left service door.
Remove air filter cover bolt and cover.
Inspect filter; wash if dirty, replace if damaged.
Wash with nonflammable solvent or detergent/water mixture; rinse thoroughly.
After drying, oil filter lightly and remove excess; do not wring out.
Wipe case and cover, reinstall filter, cover, bolt, and service door.

Engine Oil Level – Check maintenance

⚠ Non-detergent and 2-stroke oils will damage the engine

Tools: funnel

Open right service door, remove oil level gauge, wipe clean.
Re-insert gauge without screwing in to check level.
If low, add recommended oil via funnel to upper mark.
Install and tighten gauge, close service door.

Engine Oil – Change maintenance

Tools: oil funnel, drain container

Run engine to normal operating temperature, then stop.
Close vacuum relief valve to off.
Open right service door, remove and wipe oil level gauge.
Attach oil funnel, tilt generator to drain crankcase into container.
Refill oil and check level.
Install and tighten gauge, close service door.
Dispose of used oil properly.
Start engine briefly and check for leaks.
Stop engine and recheck oil level.

Fuel Level - Check maintenance

⚠ Fuel in well-ventilated area with engine stopped and cool

Check the fuel level gauge.
If low, remove fuel cap.
Check strainer; clean if dirty.
Add fuel, using stabilizer if unit will sit.
Install fuel cap after fueling.

Spark Arrestor - Inspect/Clean/Replace maintenance

⚠ Hot surface; do not perform until muffler has cooled

Tools: wire brush, screwdriver

Allow muffler to cool.
Remove screws and spark arrestor.
Clean with soft wire brush; replace if damaged.
Align mounting holes and reinstall with screws.

Spark Plug – Inspect/Adjust/Replace maintenance

⚠ Do not perform with engine running

Tools: plug wrench or spark plug socket, feeler gauge

Turn generator switch off.
Remove screws to remove outer side panel.
Remove spark plug boot and access cover.
Remove spark plug with plug wrench or socket.
Visually inspect; replace if insulator cracked or electrode damaged.
Measure gap with feeler gauge; adjust by bending side electrode.
Check spark plug washer condition.
Install spark plug and tighten to 9 ± 2 lb ft (12.5 ± 2 Nm).
Reattach boot, cover, and side panel.

Storage for more than 3 months maintenance

⚠ Gasoline is extremely flammable and explosive

Remove dirt, rust, grease, and oil; do not pressure wash.
Inspect exterior and repair as needed.
Drain fuel in well-ventilated area with engine stopped and cool.
Remove fuel cap, turn generator over to drain gasoline into container.
Reinstall fuel cap, run engine until it stops to drain remaining fuel.
Change engine oil.
Remove spark plug, pour small amount of oil into cylinder; reinstall spark plug without boot.
Turn generator switch off, move to storage, cover generator.

Recoil Start operation

Isolate generator from utility.
Unplug electrical devices from receptacles.
Turn Engine Smart Control Switch off.
Open vacuum relief valve on fuel cap by rotating clockwise to on.
Turn generator switch to choke position.
Pull starter handle until resistance felt, then pull quickly; repeat if needed.
After starting, turn generator switch to on position.

Starting the Engine - Electric Start operation

Turn fuel valve to ON position
For cold engine, pull choke knob out
Turn generator switch to START position
Release switch when engine starts
Once engine starts, slowly push choke knob in

Starting the Engine - Recoil Start operation

Turn fuel valve to ON position
For cold engine, pull choke knob out
Turn generator switch to ON position
Slowly pull starter handle until resistance felt
Quickly pull the handle with full force
Once engine starts, slowly push choke knob in

Starting the generator operation

Open fuel valve to OPEN position
Open choke
Rotate start switch to START position
After 10-15 seconds close choke
Pull recoil cord to start

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Common questions

What is the displacement of the Caterpillar OHV?

The Caterpillar OHV has a displacement of 79.7 liters.

Which generators use the Caterpillar OHV engine?

The Caterpillar OHV powers 3 generator set(s), including Caterpillar INV2000, Caterpillar RP3600, Caterpillar RP5500.

What is a common problem with the Caterpillar OHV engine?

A commonly reported issue on generators using the Caterpillar OHV is: Engine Will Not Start. Cause: Generator switch in the off “0” position. Fix: Turn the generator switch to the correct position..