Cummins/Onan 6.5NH - 3CR / 6000 A — Gaseous Fuel Carburetor Adjustment
Adjustments
For the Cummins/Onan 6.5NH - 3CR / 6000 A, from the Cummins/Onan service manual.
Applies to: Cummins/Onan NH engine
Procedure
- Set preliminary settings: 800 BTU gas about six turns open, 1,100 BTU gas 3-1/2 turns open, propane about three turns open; idle screw two turns open.
- For manual starting, gas should be above 800 BTU per cubic foot and temperature above 30 F; load disconnected or minimum.
- Allow the engine to warm up thoroughly.
- Apply full load and turn the load adjust screw in until the engine loses speed from lack of fuel, then slowly back out until it carries full load smoothly.
- Remove all load and adjust the idle screw in the same manner; check operation at various loads.
Tools required
- Screwdriver Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- 800 BTU: about 6 turns open
- 1,100 BTU: 3-1/2 turns open
- Propane: about 3 turns open
- Idle screw: 2 turns open
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.