Carburetor Symptoms and Actions

Unstable idle speed

1. Remove foreign material/dirt from pilot screw and jet.
2. Replace the pilot screw.
3. Set correct idle speed.

Poor performance at low speed

1. Remove foreign material/dirt from pilot screw and jet.
2. Clean pilot jet air path.

Engine will not start

1. Remove foreign material/dirt from pilot jet.
2. Clean pilot jet air path.

Difficult starting

1. Remove foreign material/dirt from pilot jet.

Engine starts but stops quickly

1. Remove foreign material/dirt from pilot jet.

Engine speed won’t increase

1. Remove foreign material/dirt from main jet.
2. Clean or replace main jet.

Poor performance at high speed

1. Remove foreign material/dirt from main nozzle.
2. Clean or replace main nozzle.

Unstable engine speed

1. Remove foreign material/dirt from main nozzle and valve seat.
2. Clean or replace main nozzle.

Overflow or gasoline leak

1. Check and clean float valve.
2. Check float for obstruction or wear.

Water inside float chamber

1. Drain or clean float chamber.

Float doesn’t move properly

1. Remove foreign material from around float pin.

Float valve worn or coated with foreign material/dirt

1. Clean or replace the float valve.

Pilot screw and limiter cap damaged

1. Fit a rubber tube to the stub of the pilot screw and unscrew.
2. Install a new pilot screw and adjust to the specified position.
3. Apply LOCTITE 638 and install limiter cap.