Commercial Mowers

Basic Adjustment

The basic carb adjustments are about 1 turn out for the low speed screw and 1 and a 1/2 turns out for the high speed. This should get the engine running.

Most settings for low speed are around 1 to 1 and 1/4 and 1 and 1/2 to 1 and 3/4 turns out for high speed.

Final adjustments

The LOW speed screw (Engine at Idle Speed) should be adjusted (OUT) until the engine puffs out some black smoke, runs a little rough and appears to be getting too much fuel. Then turn the screw (IN) slightly until engines runs smooth.

Next adjust the HIGH speed screw with the engine running fast (Full Throttle). Turn the HIGH speed screw (OUTWARDS) until the engine puffs black smoke or begins to run rich. Then back the screw (IN) about 1/4 turn.

Once the engine is adjust correctly, going from idle to full throttle the engine will not die, bog down, hesitate, etc.

These procedures will also work with most other small enginnes.