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Cummins/Onan EH09-2 Engine

The Cummins/Onan EH09-2 is a 0.09 L 1-cylinder forced air-cooled,4-cycle,single cylinder ohv type gasoline engine engine rated at 4200 rpm. It powers generator sets from Cummins/Onan, including the P1100, P1700i and P1700ie.

Also known as: Cummins Onan EH09-2

Part of the Cummins/Onan EH09 engine family — 2 variants share parts & fitment.

0.0858 L

Displacement

Cylinders

4200 rpm

Rated speed

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

Engine specifications

Displacement	0.0858 L
Cylinders	1
Aspiration	Forced air-cooled,4-cycle,single cylinder OHV type gasoline engine
Rated speed	4200 rpm

Generator sets powered by this engine

Cummins/Onan P1100 Cummins/Onan P1700iCummins/Onan P1700ie

How to read your Cummins/Onan engine serial & model number →

Common problems

When No Electricity Is Generated at Receptacle
Fix: Check if the DC circuit breaker is turned OFF. Check if the Overload Lamp is turned ON (Red). Check AC receptacle and DC terminals for loose connection. Check to see if engine starting was attempted with appliances already connected to generator. Depress the circuit breaker into ON position, after making sure the electric appliances are in the normal condition. Stop the engine and check the appliances and/or generator for overloading. Secure connection if necessary. Turn off switch on the appliance, and disconnect cable from receptacle. Reconnect after generator has been started properly.
When Engine Fails to Start
Fix: Check if engine switch is in its proper position. Check fuel level. Check to make sure generator is not connected to an appliance. Check spark plug for contamination. Check engine oil level. Check spark plug for loose spark plug cap. Turn engine switch to "(CHOKE)" position. If empty, refill fuel tank making sure not to overfill. If connected, turn off the power switch on the connected appliance and unplug. Remove spark plug and clean electrode. If the engine oil level is low, add the oil to the upper level line on the oil gauge. If loose, push spark plug cap back into place.
When No Electricity Is Generated at Receptacle:
Fix: Check if the AC circuit breaker is turned OFF. Check AC receptacle and DC terminals for loose connection. Check to see if engine starting was attempted with appliances already connected to generator. Stop the engine and check the appliances and/or generator for overloading. Secure connection if necessary.
When generator engine fails to start after several attempts, or if no electricity is available at the output socket
Fix: Check the following chart. If your generator still fails to start or generate electricity, contact your nearest Cummins dealer or service shop for further information or corrective procedures.
When Engine Fails to Start:
Fix: Check if the AC circuit breaker is turned OFF. Check AC receptacle and DC terminals for loose connection. Check to see if engine starting was attempted with appliances already connected to generator. Stop the engine and check the appliances and/or generator for overloading. Secure connection if necessary.
Unit Starts And Runs, Then Stops When The Start Switch Is Released
Cause: Low fluid levels, Possible overheating, Other functional problem
Fix: Check & bring all fluids up to the appropriate levels, Check for blocked air flow or other possible causes of overheating, Contact an Cummins Onan Authorized RV Service & Parts Dealer
Unit Runs Then Surges
Cause: Loose or worn spark plug leads, Defective ignition coil, wiring, or control components, Faulty spark plug, Governor out of adjustment, Combustion air pre-heat malfunction, Carburetor icing, Carburetor varnishing
Fix: Check spark plug leads at spark plug & ignition coil, Contact an Cummins Onan Authorized RV Service & Parts Dealer, Remove spark plug & clean or replace, Contact an Cummins Onan Authorized RV Service & Parts Dealer, Contact an Cummins Onan Authorized RV Service & Parts Dealer, Contact an Cummins Onan Authorized RV Service & Parts Dealer
Unit Runs Then Stops, Or Stops When Driving Around A Corner
Cause: Low fuel level, Low oil level, Excess oil
Fix: Add fuel, Add oil, Reduce engine oil level
Fails To Crank
Cause: Low battery, Bad battery connection, Blown fuse
Fix: Check battery fluid level, Clean & tighten all battery & cable connections, Replace fuse on control panel
Exhausting Black Smoke
Cause: Dirty air filter
Fix: Replace air filter
Cranks But Won’t Start
Cause: Fuel below generator pickup level in tank, Fuel supply shutoff valve closed, Carbon deposits on spark plug(s), Low oil level
Fix: Add fuel, Fully open fuel supply valve, Remove spark plug(s) and replace, Add oil
Circuit Breaker Trips
Cause: Overloaded circuit
Fix: Turn-off some of the electrical load, and reset the circuit breaker

Compiled from service & troubleshooting documentation across every generator set that uses the Cummins/Onan EH09-2.

Maintenance schedule

Item	Spec	Capacity	Part #	Interval
Air filter	Replace air cleaner element		—	200 hr
Fuel filter			—	200 hr
Oil filter			—	100 hr
Battery			—	8 hr
Belt			—
Coolant			—	100 hr
Oil	Change engine oil	20.0 hours	—	100 hr
Spark plug	Adjust the electrode gap to 0.6 to 0.7 mm.		—	500 hr

Pooled from every document that names this exact engine — confirm the interval and part number against your unit's serial number.

Service intervals

Item	Action	Hours	Months	Notes
Oil level	Check	8 hr		Check oil daily or every 8 hours of operating time; perform a general inspection daily per Operator's Manual
Engine oil	Change	50 hr		First service — Break-in: change engine oil after the first 20-50 hours of operation (RV QG/RV QG RM); perform at least once a year
Battery & connections	Clean		1 mo	Clean & check battery & connections; perform more often in hot weather
Oil/oil filter - Quiet Diesel 10000/12500	Change			First service — Break-in then repeat (footnotes 1-4, 2-4)
Oil/oil filter - Quiet Diesel 5500	Change			First service — Break-in then repeat (footnotes 1-4, 2-4)
Oil/oil filter - Quiet Diesel 7500/8000	Change			First service — Break-in then repeat (footnotes 1-4, 2-4)
Spark arrester	Clean		1 mo	Clean arrester; perform sooner if engine performance deteriorates

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
Gap	Air gap between flywheel and pulsar coil	0.5	mm	measured with a feeler gauge
Other	Power output change with altitude	3.5	% decrease per 1000 ft increase	typical power output change based on ambient conditions
Other	Power output change with temperature	1	% decrease per 10 degF increase	typical power output change based on ambient conditions
Resistance	Insulation resistance (AC receptacle output to ground)	1 MΩ or more	MΩ	measured with AC breaker ON; normal
Resistance	Insulation resistance at time of shipment from factory	10 MΩ or more	MΩ	original factory value
Resistance	Oil sensor continuity	0	Ω	below the lower oil level: ON (continuity); above lower level: OFF (non-continuity ∞)
Resistance	Stator winding resistance Red-Blue / Blue-White / White-Red	1.2	Ω	AC 120V specification
Resistance	Stator winding resistance Red-Blue / Blue-White / White-Red	4.2	Ω	AC 230V and AC 240V specification
Resistance	Yellow-Yellow/Blue (Diode Rectifier connector) winding resistance	2.1	Ω	all AC specifications
Speed	Engine revolution (correct, for troubleshooting)	4100-4300	rpm	turn the APS switch to OFF
Temperature	Ambient conditions for rated power output	77	degF	with muffler and RV enclosure, per ISO 8528-1; altitude 500 ft (152.4 m), 99 kPa dry
Temperature	Surrounding temperature for stator resistance measurement	20	°C	reference condition
Torque	Base inverter (M8 x 20 bolt and washer, M6 flange nut)	9.0-11.0	N·m	90-110 kgf·cm (6.6-8.1 ft·lbs)
Torque	Blower housing (M8 x 55mm, M8 x 90mm flange bolts)	18.0-20.0	N·m	180-200 kgf·cm (13.3-14.8 ft·lbs)
Torque	Case body bottom (M6 x 18mm flange bolt)	2.0-3.0	N·m	20-30 kgf·cm (1.5-2.2 ft·lbs)
Torque	Cylinder baffle / ignition coil bracket (M8 x 16mm, M6 x 12mm flange bolts)	3.0-5.0	N·m	30-50 kgf·cm (2.2-3.7 ft·lbs)
Torque	Flywheel (M8 x 25 bolt and washer)	19.0-21.0	N·m	190-210 kgf·cm (14.0-15.5 ft·lbs); wipe oil from tapered shaft and hole
Torque	Front frame / inverter unit / fuel cock bracket / case body-control panel / rear cover	3.0-4.0	N·m	30-40 kgf·cm (2.2-2.9 ft·lbs)
Torque	Ignition coil / recoil starter / air cleaner base plate (M6 x 14mm flange bolt, M8 flange nut)	7.0-9.0	N·m	70-90 kgf·cm (5.2-6.6 ft·lbs)
Torque	Muffler (M8 x 80mm flange bolt, M6 flange nut)	11.0-13.0	N·m	110-130 kgf·cm (8.1-9.6 ft·lbs)
Torque	Rear cover and stator (M6 x 25mm flange bolt)	10.0-11.0	N·m	100-110 kgf·cm (7.4-8.1 ft·lbs)
Torque	Rotor (M6 x 20mm flange bolt)	10.0-12.0	N·m	100-120 kgf·cm (7.4-8.9 ft·lbs)
Voltage	AC output voltage range 120V/60Hz	117-126	V	at rated amperage and rated rpm
Voltage	AC output voltage range 230V/50Hz	225-242	V	at rated amperage and rated rpm
Voltage	AC output voltage range 240V/50Hz	235-252	V	at rated amperage and rated rpm

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	Capacity	Notes
Coolant	50/50 ethylene glycol based antifreeze and water			Mix thoroughly before adding; use clean soft tap water, distilled water or pure rain; select high quality antifreeze with corrosion inhibitors
Engine oil	4-stroke automotive detergent oil of API service class SE or higher (SG, SH or SJ is recommended)	API SE or higher	0.4 L	Specification table also lists oil pan capacity 0.36
Engine oil	SAE 10W-30 / 10W-40 / 0W-30 / 5W-30			Use viscosity chart to select grade for expected ambient temperature range; avoid mixing grades or brands
Engine oil	SAE 15W-40	API CF, CF-4, CG-4, CH-4, CI-4 or CJ-4 (diesel)		OnaMax 15W-40 #326-5336; multi-grade recommended year-round in liquid-cooled engines; synthetic oil not recommended
Engine oil	SAE-30	API SJ, SL or SM (gasoline)		OnaMax SAE-30 #326-5339; preferred summer grade for optimum oil consumption control in air-cooled engines
Fuel	ASTM No.2-D / No.1-D / No.2-DLS / No.1-DLS / B5 Biodiesel	minimum Cetane number 45		No.2-D or No.2-DLS above 23 degF; No.1-D or No.1-DLS below 23 degF; B5 Biodiesel above 50 degF; use No.1 diesel below 32 degF and during long light-load periods; cloud point at least 10 degF below lowest expected fuel temperature
Fuel	Automotive Unleaded Gasoline		3.5 L	Fuel tank capacity 3.5 L
Fuel	HD-5 grade liquid propane	at least 90% propane		Fuels other than HD-5 can contain more than 2.5% butane causing poor vaporization/starting below 32 degF
Fuel	Regular unleaded gasoline	Ethanol blend not more than 10% ethanol; methanol blend not more than 5% methanol		Use fresh gas, not more than 30 days old; fuel stabilizer extends fuel life
Grease	Grease (preferably heat resistant) or mobile oil			Apply to recoil starter rotation parts, friction parts and spring
Other	Cummins Onan Premium Fuel System Cleaner		12.0 oz	Treats up to 24 gallons of gasoline; #326-5342
Other	OnaFresh GXLP fuel stabilizer		16.0 oz	Treats 40 gallons of gasoline; #326-5365

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

Procedures

Air gap adjustment of flywheel and pulsar coil adjustment

Tools: Feeler gauge

Adjust the air gap between flywheel and pulsar coil to 0.5 mm with a feeler gauge.
Attach the pulsar coil to the engine and tighten the bolt in place.

AC output measuring diagnostic

Tools: AC voltmeter, AC ammeter, Frequency meter

Use a circuit with a load such as a hot plate or lamp with a power factor of 1.0.
Adjust the load and rpm.
Check that the voltage range is as specified at the rated amperage and rated rpm.

Measuring insulation resistance diagnostic

⚠ If insulation resistance is less than 1 MΩ, disassemble the generator and measure stator, rotor and control panel individually.

⚠ Insulation failure may cause electrical leak which may result in electrocution.

Tools: Megger tester (500 V range)

Short-circuit the terminals of an AC receptacle using a wire to discharge remaining electricity.
Connect the megger tester across either one output terminal of the AC receptacle and the ground terminal.
Measure with the AC breaker on.
An insulation resistance of 1 MΩ or more is normal (factory value is 10 MΩ or more).

Recoil starter assembly maintenance

⚠ Wear protective goggles before starting assembly.

⚠ Be sure the retaining ring is fitted into the grooves.

Tools: Protective goggles

Install the ratchet and fasten it with retaining ring E.
Install the spiral spring in the reel.
Apply grease to the case.
Properly orient the inner end of the spring.
Hold the reel and softly drop it into the case from the top.
Move the reel gently counter-clockwise, making sure the spring catches.
Install the ratchet guide and return spring into the reel.
Install the friction spring, friction plate and retaining ring C.
Thread the rope through the reel and tie the end.
Wind the rope clockwise seven times with the rope hanging from the reel.

Recoil starter disassembly maintenance

⚠ Wear protective goggles before starting disassembly.

⚠ The pull of the spring is maximized while the rope is fully pulled out; do not release it suddenly.

⚠ Place the reel on a flat table without dropping or shaking.

Tools: Long-nose pliers, Retaining-ring pliers, Protective goggles

Hold the starter handle and pull the starter rope out.
Pull out all of the rope, and align the rope guide and the knot of the rope inside the reel.
Hold the reel with both thumbs so fingers do not become entangled.
Pull the knot of the rope out from the reel and loosen it.
Slowly rewind the rope until the reel stops while controlling the reel with both thumbs.
Hold the case and remove retaining-ring C with the ring pliers.
Beginning at the top, remove the retaining-ring, friction plate and ratchet.
Move the reel left and right at 1/4 turns until it moves smoothly.
Slowly lift the reel, removing it from the case.

Disassembly procedures repair

⚠ Memorize the location of each part when disassembling; tag parts for reassembly.

⚠ Remove battery before disassembly.

⚠ Do not clean electrical parts with oil or water.

Tools: Screw driver, Pliers, 10mm Box wrench, 12mm Box wrench, Flywheel puller

Remove the side panels (Left, Right).
Remove the rear cover (four screws).
Remove the rolling wire and choke wire.
Remove the recoil starter handle and guide.
Remove the control panel.
Remove the case body (Left, Right).
Remove the rear frame.
Remove the fuel cock bracket.
Remove the fuel tank and fuel cock.
Remove the control panel and disconnect the three couplers.
Remove the inverter unit (two couplers).
Remove the fuel pipes (carburetor side and crank case side).
Remove the air cleaner and carburetor.
Remove the front frame.
Remove the base inverter, stator/rear cover, rotor, blower housing, flywheel, recoil starter, muffler, ignition coil and cylinder baffle.

Reassembly procedures repair

⚠ Wipe off any oil from the tapered shaft and hole before assembling the flywheel.

⚠ Do not forget to put the 2 pieces of pipe knock.

⚠ Avoid damaging the magnet of the rotor.

Tools: Screw driver, 10mm Box wrench, 12mm Box wrench, Feeler gauge

Install the cylinder baffle.
Install the ignition coil into the ignition coil bracket.
Install the muffler.
Install the recoil starter to the crankcase.
Install the flywheel.
Adjust the air gap between flywheel and pulsar coil to 0.5 mm with a feeler gauge.
Install the pulsar coil and grommet.
Install the blower housing.
Install the rotor.
Install the rear cover and stator into the rotor.
Install the base inverter into the engine main body.
Install the front frame (L) and (R) onto the base inverter.
Install the air cleaner base plate and carburetor.
Install the air cleaner element and cover.
Install the fuel pipes, inverter unit and couplers, fuel tank and fuel cock, rear frame, case body and control panel, recoil starter guide, choke/rolling wires, rear cover and side panels.

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

Parts cataloged across the Cummins/Onan EH09 family

Part #	Description	Category
284-75501-03	GROMMET	Harness
284-79581-03	ENGINE HARNESS	Harness
34K-21101-03	ENGINE HARNESS	Harness
002-38080-00	FLANGE NUT	Service part / kit
004-35061-00	SCREW and WASHER	Service part / kit
011-00600-10	FLANGE BOLT	Service part / kit
011-00600-30	FLANGE BOLT	Service part / kit
056-90000-20	PURSE LOCK	Service part / kit
226-75101-03	CLAMP	Service part / kit
284-67101-03	Y CONNECTOR	Service part / kit
284-79350-01	FLYWHEEL	Service part / kit
284-79530-01	IGNITION COIL	Service part / kit
284-79540-01	PULSER COIL	Service part / kit
284-79561-01	IGNITION COIL BRACKET	Service part / kit
33K-99001-00	ACCESSORY TOOL KIT	Service part / kit
230-75801-03	SENSOR RETAINER	Sensor
230-76301-11	OIL SENSOR	Sensor
065-01403-80	SPARK PLUG	Spark plug

Parts cataloged across all variants of this engine family — verify the exact part fits your specific variant and serial number before ordering.

Common questions

What is the displacement of the Cummins/Onan EH09-2?

The Cummins/Onan EH09-2 has a displacement of 0.0858 liters with 1 cylinders.

Which generators use the Cummins/Onan EH09-2 engine?

The Cummins/Onan EH09-2 powers 3 generator set(s), including Cummins/Onan P1100, Cummins/Onan P1700i, Cummins/Onan P1700ie.

How often should you change the oil in the Cummins/Onan EH09-2?

The Cummins/Onan EH09-2 oil change interval is every 100 hours.

What is a common problem with the Cummins/Onan EH09-2 engine?

A commonly reported issue on generators using the Cummins/Onan EH09-2 is: When No Electricity Is Generated at Receptacle. Fix: Check if the DC circuit breaker is turned OFF. Check if the Overload Lamp is turned ON (Red). Check AC receptacle and DC terminals for loose connection. Check to see if engine starting was attempted with appliances already connected to generator. Depress the circuit breaker into ON position, after making sure the electric appliances are in the normal condition. Stop the engine and check the appliances and/or generator for overloading. Secure connection if necessary. Turn off switch on the appliance, and disconnect cable from receptacle. Reconnect after generator has been started properly..