Service parts for the 4000
Grouped by system, with how many of each the parts manual calls for.
Air intake
1 requiredOil system
1 requiredPrices captured from merchant listings; some links are affiliate links. Confirm against your serial number before ordering.
Specifications
| Standby power | 4 kW |
|---|---|
| Oil capacity | 3.3 L |
Maintenance & consumables
for the Cummins/Onan EM (SN5782U1G2RA)| Item | Spec | Capacity | Part # | Interval | |
|---|---|---|---|---|---|
| Air filter | 140-0495 | 150 hr | Amazon eBay $16.99 NAPA $29.20 | ||
| Fuel filter | — | 300 hr | |||
| Oil filter | 122-0406 | 150 hr | Amazon eBay $17.00 NAPA $11.34 | ||
| Battery | — | 150 hr | |||
| Belt | — | ||||
| Coolant | — | ||||
| Oil | 3.5 quarts | — | 50 hr | ||
| Spark plug | 167-0237 | 300 hr | Amazon eBay $14.00 NAPA $3.97 |
Common questions
What size generator is the Cummins/Onan 4000?
The Cummins/Onan 4000 is rated 4 kW standby.
What engine does the Cummins/Onan 4000 use?
The Cummins/Onan 4000 is powered by the Cummins/Onan EM (SN5782U1G2RA) engine.
What's the oil capacity on a Cummins/Onan 4000?
The Cummins/Onan EM (SN5782U1G2RA) engine in the Cummins/Onan 4000 has an oil capacity of 3.3 liters.
What oil filter fits the Cummins/Onan 4000?
The Cummins/Onan 4000 uses oil filter part number 122-0406.
What air filter fits the Cummins/Onan 4000?
The Cummins/Onan 4000 uses air filter part number 140-0495.
Troubleshooting
6Symptoms & remedies
| Symptom | Cause | Remedy |
|---|---|---|
| The engine fails to crank. | Try starting at the genset rather than at the remote control. | |
| The engine fails to crank. | Fuse F1 on the control panel has blown. | Replace fuse F1 on the control panel if it has blown. |
| The engine fails to crank. | Loose or dirty positive (+) and negative (-) battery cable connections at the battery and the genset. | Clean and tighten the positive (+) and negative (-) battery cable connections at the battery and the genset. |
| The engine fails to crank. | Battery discharged. | Recharge the battery. Refer to the battery manufacturer's recommendations. |
| The engine cranks slowly. | Air conditioner and other large loads connected. | Disconnect the air conditioner and other large loads. |
| The engine cranks slowly. | Loose or dirty positive (+) and negative (-) battery cable connections at the battery and the genset. | Clean and tighten the positive (+) and negative (-) battery cable connections at the battery and the genset. |
Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing. Full Cummins/Onan 4000 troubleshooting guide (26 entries) →
Parts
6| Part # | Description | Qty | System | |
|---|---|---|---|---|
| 146-0466 | Fuel Pump Kit | Pump | eBay | |
| 149-1983 | Fuel Pump Cover Kit | Pump | eBay | |
| SN5782U1G2RA | Engine | 1 | Engine | Amazon eBay |
| 150-2460 | Governor Control Rod Kit | Service part / kit | eBay | |
| 515-0227 | Key kit | 1 | Service part / kit | Amazon eBay |
| 541-0370 | Exhaust Flange Adapter Kit | Service part / kit | eBay |
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
| Rating | Load | L/h | gal/h |
|---|---|---|---|
| Prime | 0.6 | 2.3 | |
| Standby | 0.4 | 1.5 |