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Home›Cummins/Onan›Cummins/Onan 4B3.9

Cummins/Onan 4B3.9 Generator Set

The Cummins/Onan 4B3.9 is a 37 kW (50 kVA) prime generator set powered by a D381036MX02 engine. It holds 132 L (34.9 gal) of coolant, with a maximum ambient rating of 40 °C. The set weighs about 316 kg (697 lb).

3.9 L
Displacement
3
Document types

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

Specifications

Prime power37 kW
Coolant capacity132 L
Max ambient40 °C
Dry weight316 kg

Engine

D381036MX02
Coolant capacity132.0 L
Displacement3.9 L
AspirationNaturally Aspirated
Rated speed1500 rpm

Common questions

What engine does the Cummins/Onan 4B3.9 use?

The Cummins/Onan 4B3.9 is powered by the D381036MX02 engine.

Parts

4
Part #DescriptionQtySystem
3822509injector puller1Injector PartsGeek
3823276injector bore brush1Injector PartsGeek
3824469fuel pump gear puller1Fuel pump PartsGeek
3377259bosch timing tool (ve)1Service part / kit PartsGeek

Service, wear & replacement parts referenced for this model and its engine — confirm the exact part for your serial number. See the full parts catalog to search and cross-reference.

Fuel consumption

RatingLoadL/hgal/h
Continuous100%7.882.08
Prime25%3.710.98
Prime50%5.411.43
Prime75%7.531.99
Prime100%9.72.6

Available documents

Engine spec — 4000134 (Cummins/Onan)Spec sheet — fr90431 (Cummins/Onan)Spec sheet — fr90432 (Cummins/Onan)Service manual — CONTENTS-Cummins-B-Series-Troubleshooting-Repair-3666087-588pages (Cummins/Onan)