Kohler M18 / M20 — Adjust Carburetor
Adjustments
For the Kohler M18 / M20, from the Kohler service manual.
Applies to: Kohler M18 / M20 engine
Before you start
- Do not force tapered adjusting needles
Procedure
- Stop engine; turn adjusting needles in clockwise until lightly bottomed.
- Set preliminary settings: main fuel 2-1/2 turns, idle fuel 1 turn out.
- Run engine at half throttle 5-10 minutes to warm up.
- Final main fuel: set needle midway between rich and lean settings.
- Final idle fuel: set needle using same procedure; idle speed not to exceed 1500 RPM.
- Set idle speed to 1200 RPM (plus or minus 75) with idle speed screw.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Main fuel preliminary 2-1/2 turns
- Idle fuel preliminary 1 turn
- Idle speed 1200 RPM
Source: Kohler 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.