Troubleshooting Fuel System Problem: Carburetor Too Rich (0-1/4 Opening) Condition Remedy 1. Choke valve will not seat 1. Adjust — service — replace choke cable — assembly 2. Idle fuel adjuster screw out of adjustment 2. Adjust idle fuel adjuster screw 3. Float/needle jet obstructed — damaged — adjusted incor- 3. Remove obstruction — replace needle jet — float rectly 4. Pilot jet loose 4. Tighten pilot jet Problem: Carburetor Too Rich (1/4-3/4 Opening) Condition Remedy 1. Replace pilot jet 1. Pilot jet too large 2. Float/needle jet obstructed — damaged — adjusted incor- 2. Remove obstruction — replace needle jet — float rectly 3. Tighten — replace main jet 3. Main jet loose — too large 4. Remove obstruction 4. Primary air passage obstructed Problem: Carburetor Too Rich (3/4-WOT Opening) Condition Remedy 1. Main jet loose — too large 1. Tighten — replace with smaller main jet 2. Float/needle jet obstructed — damaged — adjusted incor- 2. Remove obstruction — replace needle jet — float rectly Problem: Carburetor Too Lean (0-1/4 Opening) Condition Remedy 1. Choke valve hanging open 1. Adjust — service choke cable — valve assembly 2. Pilot jet — outlet obstructed 2. Remove obstruction 3. Float/needle jet obstructed — damaged — adjusted incor- 3. Remove obstruction — replace needle jet — float rectly Problem: Carburetor Too Lean (1/4-3/4 Opening) Remedy Condition 1. Pilot jet — outlet — main jet obstructed 1. Remove obstruction 2. Float/needle jet obstructed — damaged — adjusted incor- 2. Remove obstruction — replace needle jet — float rectly Problem: Carburetor Too Lean (3/4-WOT Opening) Condition Remedy 1. Main jet obstructed — too small 1. Remove obstruction — replace with larger main jet 2. Float/needle jet obstructed — damaged — adjusted incor- 2. Remove obstruction — replace needle jet — float rectly Problem: General Fuel System (Engine Cuts Out at High RPM) Condition Remedy 1. Fuel delivery inadequate 1. Repair — replace hose 2. In-line fuel filter obstructed — damaged 2. Remove obstruction — replace in-line fuel filter 3. Gasoline contaminated 3. Replace gasoline — de-ice — clean carburetor 4. Gas-tank vent — hose obstructed 4. Remove obstruction — replace vent — hose
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