Cummins/Onan — Priming the Lubrication System
Maintenance · Engine lubrication system
From a Cummins/Onan service manual — check it applies to your exact model before use.
Browse Cummins/Onan generators & specs →
Procedure
- Remove oil inlet line from turbocharger housing, fill bearing housing with clean engine lubricating oil; replace line, secure.
- Fill crankcase to 'L' (low) mark on dipstick.
- Remove plug from head of oil filter housing and connect a hand or motor-driven priming pump from a source of clean lubricating oil to the plug hole in filter housing.
- Prime until a 30 psi (207 kPa) pressure is obtained.
- Disconnect wire from fuel solenoid valve, close throttle and crank engine while maintaining an external prime pressure of 15 psi (103 kPa), for 15 seconds.
- Remove external priming equipment, replace plug in filter housing and torque to 15 to 20 ft lb (20 to 27 N·m).
- Reconnect wire to fuel shutoff valve.
- Complete oil fill to 'H' (high) mark on dipstick.
Tools required
- Hand or motor-driven priming pump Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- 30 psi (207 kPa) priming pressure
- 15 psi (103 kPa) crank pressure for 15 seconds
- 15 to 20 ft lb (20 to 27 N·m) plug torque
Source: Cummins/Onan service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.