Cummins/Onan — Field Adjustment - Carburetor

For these Cummins/Onan models: GNH, GV12.

Applies to: Cummins Onan Gv12

Procedure

1. 1. Close main gas supply valve;
2. 2. Set the carburetor power mixture adjustment valve at cen- ter between (rR" (Rich) and "L" (Lean) marks. Fig. 4-8.
3. 3. Close the idle adjustment; then open two and one-half turns. Fig. 4-9.
4. 4. Remove pipe plug and attach a pressure gauge (water manometer) between the main line passage regulator and the "Thermac" pressure reduction valve. Also remove the on the "Thermac" pressure reduction valve. See Fig. 4-10 for check points.

Source: manual:960-0010 Cummins GNH series Nat Gas Engine Service Manual (1-1966).pdf. Figures and steps are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.