VESPA GT 200, Workshop Manual

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8.1.9 Engine Tends to Cut Out at Full Throttle
Symptom Possible Cause Operation
Main jet dirty; lean carburetion Wash the jet in solvent and dry with
compressed air
Water in carburetor Empty the float chamber by using the
drain screw
Float level incorrect Restore the level in the float chamber
by bending the fuel inlet needle
thrust blade on the float so that the
float is parallel to the chamber
surface when the carburetor is in an
up-side down position
Engine tends to
cut out at full
throttle
Fuel supply circuit faulty Check and, if necessary, replace the
fuel pump. Check the vacuum intake
and the duct seal
8.1.10 Engine Tends to Stop at Idle
Symptom Possible Cause Operation
Idling jet dirty Wash in solvent and dry with
compressed air
Choke device remains activated Check: electrical connections, circuit
continuity, mechanical sliding and
power supply; replace if required
Spark plug faulty or spark
advance incorrect Replace the spark plug or check the
ignition circuit components
Compression end pressure too
low Check thermal unit seals and replace
worn components
Idle adjustment incorrect Adjust using a rev counter
Cut-off device faulty Check the operation of the valve,
membrane and spring; check if the
air adjusters and the sponge filter are
clean
Engine tends to
stop at idle
Incorrect timing Restore correct timing and check
timing system components