Yamaha F50A Service Manual page 134

POWR
Symptom: Engine does not accelerate when the throttle is opened quickly.
The engine turns off when the throttle is opened quickly.
Acceleration is tardy and the engine is likely to stop at any moment.
• Check the carburetors.
• Check the ignition system.
• Check the compression pressure of power unit.
Check the throttle cable opera-
tion.
Do the carbu-
retor throttle
valves close
simulta-
neously?
Yes
Check the needle valve of the
carburetor for debris or wear.
Debris or
wear?
Yes
Clean the carburetor, or replace
respective parts.
5-7
Power unit
No
Adjust the throttle cable.
No
Check each jet of the carburetor
for clogs or debris.
Clean or replace the respective
parts.
Clogs or
debris?
Yes
Check the ignition
No
system and the
compression pres-
sure of the engine.
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