Cummins/Onan W3M-19 — Carburetor Adjustment
Adjustments · Zenith carburetor
For the Cummins/Onan W3M-19, from the Cummins/Onan service manual.
Applies to: Cummins/Onan W3M-19, Cummins/Onan W2C engine
Before you start
- Do not turn either needle tightly into its seat or seat may be damaged
Procedure
- Run engine to normal operating temperature.
- With 1500 to 3000 watts load, turn main jet needle out 3 turns.
- Turn main jet needle in until engine loses power and speed.
- Turn needle out slowly until engine regains maximum power and speed.
- With no load, turn idle jet needle in until engine loses considerable speed.
- Turn idle jet needle out until engine runs smoothest.
- Approximate start: turn both needles in, then out about 2-1/2 turns.
Tools required
- Screwdriver Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Idle jet usually 3/4 to 1-1/2 turns open
- Do not turn needles tightly into seat
Full service-parts list: Cummins/Onan W3M-19 →
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.