The Cummins/Onan BF is a 0.66 L 2-cylinder engine rated at 3600 rpm, producing up to 11.9 kW. It holds 2.13 L (0.6 gal) of oil.
Also known as: Onan BF
| Oil capacity | 2.13 L |
|---|---|
| Displacement | 0.66 L |
| Cylinders | 2 |
| Rated speed | 3600 rpm |
| Gross power | 11 kW |
No generator set in our catalog cites this exact engine designation yet; its specifications and fault codes are documented here.
How to read your Cummins/Onan engine serial & model number →
| Code | Meaning | Remedy |
|---|---|---|
| BF | BF | |
| BFA | BFA | |
| 1 | Engine does not crank. | Check remote start control wires for continuity between the generator set and the remote start panel. Are control wires sized large enough to avoid excessive voltage drop? Replace control wires with correct wire gauge if necessary. |
| 2 | Engine cranks but does not start. | Check all terminal connections on K2 crank ignition relay. If OK, replace K2 relay. Does the fuel pump operate during cranking? Check the fuel pump lead wire connections and repair or replace as necessary. |
| 3 | Engine starts but stops when start switch is released. | Add oil as required. If oil level is OK, disconnect the low oil pressure switch lead wire and ground it to check if the engine starts and runs. Check low oil pressure switch operation and replace if necessary. |
| 4 | Engine is running - then stops. | Connect a voltmeter between remote connector plug terminal 6 and ground to check battery voltage. Replace fuse F2 if open. |
| 5 | Low battery - no charge rate. | Check condition of battery and wire connection between CR1 diode, K1 start solenoid, R2 resistor, and battery. Replace defective CR1 diode or R2 resistor if necessary. |
| 6 | Running Time Meter Inoperative. | Replace defective running time meter if necessary. |
| 7 | Battery Condition Meter Inoperative. | Replace fuse F1. Check wire connections between remote connector plug terminal 5 and the battery condition meter, and between the battery condition meter and ground. Use voltmeter to measure voltage between battery charge meter positive terminal and ground. |
| Symptom | Cause | Remedy |
|---|---|---|
| NO AC OUTPUT | . Blow fuse or circuit breaker (if used). Then replace fuse or reset circuit breaker. . Disconnected wire or lead on brushes. . Brushes not making contact with slip rings may be excessively worn. | . Look for cause and repair. |
| LOW AC OUTPUT | . External short circuit on line. Circuit problem. . Generator overloaded. . Remove part of load. . Shorted or grounded circuit in field or armature winding. | . Test for open, grounded, or shorted windings. Repair or replace as necessary. . Engine not running properly causing generator to slow down. |
| NOISY GENERATOR | . Defective bearing in end bell. . Brush rig loose. . Armature and field frame rubbing together. | . Replace bearing. . Retorque. . Check for generator misalignment and for varnish lumps between armature and field. Repair as necessary. . Turn commutator on lathe; undercut mica insulation. |
| GENERATOR OVERHEATS | . Windings and parts covered with oil or dirt. | . Clean generator. . Take necessary steps to allow for proper cooling. |
| Air intake restricted or incoming air too hot. | . Take necessary steps to allow for proper cooling. | |
| Shorted, open or grounded windings in armature or field. | . Test for open, grounded or shorted windings. Repair or replace as necessary. | |
| IT STOPS | Faulty Ignition . See 4 above (CRANKS BUT WON'T START). Out of Fuel. Refill fuel tank. Low Oil Level. Check oil levei. if low or empty, refill to proper level. | |
| LAMP INOPERATIVE | Replace F1 fuse on control. | |
| Low or Discharged Battery | Faulty Starter Faulty Start Solenoid Ignition Timing Wrong Spark Plug Gap Worn Points or Improper Gap Setting Bad Ignition Coil or Condenser Faulty Spark Plug Wires | |
| FUEL SYSTEM | Out of Fuel - Check Lean Fuel Mixture - Readjust Rich Fuel Mixture or Choke Stuck Engine Flooded Poor Quality Fuel Dirty Carburetor Dirty Air Cleaner Dirty Fuel Filter Defective Fue! Pump Wrong Valve Clearance Broken Valve Spring Valve or Valve Seal Leaking Piston Rings Worn or Broken Wrong Bearing Clearance Poor Air Circulation Dirty or Oily Cooling Fins Blown Head Gasker Insufficient Coolant Faulty Thermostat Worn Water Pump or Pump Seal Water Passages Restricted Defective Gaskets |
Fault codes and symptom→remedy steps extracted from this engine’s service/owner documentation; verify against the official manual before servicing.
| Item | Spec | Capacity | Part # | Interval | |
|---|---|---|---|---|---|
| Air filter | Air Filter Element (3 inch height) | 140-1216 | Amazon eBay | ||
| Oil filter | 122-0338 | 100 hr | Amazon eBay $13.57 | ||
| Oil | API SE or SE/CC | 2.13 L | — | 50 hr | |
| Spark plug | 0.025 inch gap | 167-0241 | 100 hr | Amazon Amazon eBay $34.86 eBay $17.97 |
Pooled from every document that names this exact engine — confirm the interval and part number against your unit's serial number.
The Cummins/Onan BF engine has an oil capacity of 2.13 liters.
The Cummins/Onan BF has a displacement of 0.66 liters with 2 cylinders.
The Cummins/Onan BF oil change interval is every 50 hours.