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Cummins/Onan 4B3.9-G2 Engine Engine

The Cummins/Onan 4B3.9-G2 is a 3.9 L 4-cylinder natural engine rated at 1500 rpm, producing up to 27 kW. It powers generator sets from Cummins/Onan, including the 35 DGBB, 40 DGBC, C40 D6 and C45D5. It holds 17.3 L (4.6 gal) of coolant.

Also known as: Cummins 4B3.9-G2

Part of the Cummins/Onan 4B3.9 engine family — 3 variants share parts & fitment.

3.9 L
Displacement
4
Cylinders
1500 rpm
Rated speed
27 kW
Gross power

Engine specifications

Coolant capacity17.3 L
Displacement3.9 L
Cylinders4
AspirationNatural
Rated speed1500 rpm
Gross power27 kW

Parts cataloged across the Cummins/Onan 4B3.9 family

6
Part #DescriptionCategory
928-0502Bother_service
928-0506other_service
960-0135other_service
960-0504Aother_service
960-0505other_service
960-12other_service

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 4B3.9-G2?

The Cummins/Onan 4B3.9-G2 has a displacement of 3.9 liters with 4 cylinders.

Which generators use the Cummins/Onan 4B3.9-G2 engine?

The Cummins/Onan 4B3.9-G2 powers 6 generator set(s), including Cummins/Onan 35 DGBB, Cummins/Onan 40 DGBC, Cummins/Onan C40 D6, Cummins/Onan C45D5, Cummins/Onan DGBB.