lA NOSJP Ito) I I -----------------------------------------------------CARBURETOR TUNING
Trouble
Diagnosis
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Adjustment
Poor performance at Return the starter lever to its seated position so that Starter valve is left open high speeds: the starter valve is fully closed. • Power loss • Poor acceleration
Clogged air vent Clogged or loose main air jet
Remove and clean the air vent. • Remove the main jet, clean it with compressed air and then install it. • Make sure that the main jet is fully tightened.
Clogged fuel line
Clean or replace the fuel line.
Dirty fuel tank
Clean the fuel tank.
Air leaks into the fuel Tighten or replace the fuel line joint. line Low fuel pump perforRepair or replace the fuel pump. mance Clogged fuel filter Clogged intake Abnormal combus- Lean mixture tion: Dirty carburetor • Backfiring Overflow:
Replace the fuel filter. Remove any obstructions (Le. ice). Clean and adjust the carburetor. Clean the carburetor.
Dirtyorcloggedfuelline Clean or replace the fuel line. Clogged air vent
• Poor idling
Clogged float valve • Poor performance at low, mid-range, and Scratched or unevenly high speeds worn float valve orvalve • Excessive fuel con- seat sumption Broken float
Clean the air vent. • Disassemble and clean the float valve. • Do not scratch the valve seat. • Clean or replace the float valve and valve seat. • The valve seat and body must be replaced together. Replace the float.
• Hard starting
Check, and if necessary, replace the following parts:
• Power loss
.Float tang
• Poor acceleration
Incorrect float level
• The float (replace the entire float assembly). • The arm pin.
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