_ _ _ _ _ _ _ _ _ _ IIANOSJPI·oll CARBURETOR TUNING .
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2E321
Troubleshooting
Trouble Hard starting
Add gasoline Excessive use of starter Clean spark plug (Excessively opened choke) Fuel passage is clogged or frozen
Poor idling (Related troubles) • Poor performance at low speeds • Poor acceleration • Slow response to throttle • Engine tends to stall
Remedy
Check point Insufficient fuel
Clean
Correct Overflow Improper idling speed adjustment Adjust idling speed • Pilot screw
• Throttle stop screw
Adjust
Damaged pilot screw
Replace pilot screw Clean
Clogged bypass hole
Clogged or loose pilot Clean and retighten jet
Adjustment Return starter level to its seated position. Parts otherthan aircarburetor. • Clogged fuel tank air vent, clogged fuel filter, or clogged fuel passage. Carburetor • Clogged or frozen air vent, or clogged valve. • If water collects in float chamber, clean. (Also check for ice) Bottom the pilot screw lightly, and back it outto specification. Start the engine and turn pilot screw in and out 1/4 turn each time. When the engine runs faster, back out throttle stop screw so the engine idles at specified speed. Tightened too much - Engine speed is higher. Backed out too much - Engine does not idle.
Remove pilot jet, and blow it out with compressed air.
Air leaking into carbu- Retighten bend screw retor joint Defective starter valve seat Overflow Poor performance at mid-range speeds (Related troubles) • Momentary slow response to throttle • Poor acceleration Poor performance at normal speeds (Related troubles) • Excess fuel consumption • Poor acceleration
Clean or replace Correct
Clogged or loose pilot Clean and retighten jet
Remove pilot jet, and blow it out with compressed air.
Lean mixtures Clogged air vent
Overhaul carburetor Clean Remove the air vent pipe, and clean.
Clogged or loose main jet Overflow
Clean and retighten Check float and float valve and clean
2·34
Remove main jet, and blow it out with compressed air.