HomeEnginesCummins/Onan E125V

Cummins/Onan E125V Engine

The Cummins/Onan E125V is a 0.39 L 1-cylinder engine rated at 3600 rpm, producing up to 9.3 kW. It powers generator sets from Cummins/Onan, including the EW25W.

Also known as: Onan E125V

Part of the Cummins/Onan E125V engine family — 2 variants share parts & fitment.

0.389 L
Displacement
1
Cylinders
3600 rpm
Rated speed
9 kW
Gross power

Engine specifications

Displacement0.389 L
Cylinders1
Rated speed3600 rpm
Gross power9 kW

Generator sets powered by this engine

1
Cummins/Onan EW25W

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

Maintenance schedule

ItemSpecCapacityPart #Interval
Air filterElement Wrapper (If Equipped)140-233525 hr Amazon eBay $21.00
Fuel filterFuel Filter149-2206-0125 hr Amazon eBay $12.86
Oil filterSpin off oil filter element and discard it. Thoroughly clean filter mounting surface and make sure new gasket is inserted in the element. Apply a thin film of oil to the gasket. Spin element down by hand until gasket just touches mounting pad and then turn down an additional 1/2-3/4 turn. Do not overtighten.122-073725 hr Amazon eBay $11.99 KuduParts $11.00
BatteryDisconnect negative ground strap from the battery before working on any part of the electrical system or engine. Disconnect positive terminals before charging battery to avoid damaging ignition system alternator or regulator.
OilRun engine until thoroughly warm before draining oil. Stop the engine, place a pan under the drain outlet and remove the oil drain plug. After the oil is completely drained, replace the drain plug. Refill with oil of the correct API classification and appropriate SAE viscosity grade for the temperature conditions (refer to ENGINE SET-UP).
Spark plugReplace spark plug if it shows signs of fouling or electrode erosion.167-07654000 hr Amazon eBay

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

Parts cataloged across the Cummins/Onan E125V family

10
Part #DescriptionCategory
140-2331Air Cleaner Elementair_filter
140-2335Air Cleaner Element Wrapper (If Equipped)element_wrapper
149-2206-01Fuel Filterfuel_filter
122-0737Filteroil_filter
965-0178E125V/ E140Vother_service
965-0179E125H I E140Hother_service
965-0180P218V I P220Vother_service
965-0183P248V Floorcareother_service
C851D8pin (1/8 inch drill bit)other_service
167-0765Spark Plugspark_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 E125V?

The Cummins/Onan E125V has a displacement of 0.389 liters with 1 cylinders.

Which generators use the Cummins/Onan E125V engine?

The Cummins/Onan E125V powers 1 generator set(s), including Cummins/Onan EW25W.