Engine
Poor performance
POOR PERFORMANCE
Possible Cause
Operation
Air filter blocked or dirty
Remove the sponge, wash with water and car shampoo, then
soak it in a mixture of 50% petrol and 50% specific oil. Press
with your hand without squeezing, allow it to drip dry and refit.
Fuel nozzles or cock clogged or dirty
Dismantle, wash with solvent and dry with compressed air
Dirty or faulty vacuum-operated cock
Check the filter on the cock, remove the petrol and wash the
tank, if necessary. Replace the cock as a last resource.
Failing automatic starter on the carburettor
Check the electrical wiring and mechanical movement, replace
if necessary.
Excessive drive belt wear
Check it and replace, if necessary
Lack of compression: parts, cylinder and valves worn
Replace the worn parts
Oil level exceeds maximum
Check for causes and fill to reach the correct level
Excess of scales in the combustion chamber
Descale the cylinder, the piston, the head and the valves
Incorrect timing or worn timing system elements
Time the system again or replace the worn parts
Muffler obstructed
Replace
Inefficient automatic transmission
Check the rollers and the pulley movement, replace the dam-
aged parts and lubricate the movable guide of the driven pulley
with grease.
Wrong valve adjustment
Adjust the valve clearance properly
Overheated valves
Remove the head and the valves, grind or replace the valves
Valve seat distorted
Replace the head unit
Worn cylinder, Worn or broken piston rings
Replace the piston cylinder assembly or just the piston rings
Rear wheel spins at idle
REAR WHEEL ROTATES WITH ENGINE AT IDLE
Possible Cause
Operation
Idling rpm too high
Adjust the engine idle speed.
Clutch fault
Check the springs / clutch masses
Starting difficulties
START-UP PROBLEMS
Possible Cause
Operation
Flat battery
Check the state of the battery. If it shows signs of sulphating
replace it and bring the new battery into service charging it for
eight hours at a current of 1/10 of the capacity of the battery
itself
Faulty spark plug or incorrect ignition advance
Replace the spark plug or check the ignition circuit components
Flooded engine
Try starting-up with the throttle fully open. If the engine fails to
start, remove the spark plug, dry it and before refitting, make
the engine turn so as to expel the fuel excess taking care to
connect the cap to the spark plug, and this in turn to the ground.
If the fuel tank is empty, refuel and start up.
Incorrect valve sealing or valve adjustment
Inspect the head and/or restore the correct clearance
Rpm too low at start-up or engine and start-up system dam-
aged
Check the starter motor and the kick-starter unit
Altered fuel characteristics
Drain off the fuel no longer up to standard; then, refill
Vacuum operated cock failure
Check that fuel is adequately supplied through the pipe by ap-
plying a vacuum to the vacuum pipe
Failing automatic starter on the carburettor
Check the electrical wiring and mechanical movement, replace
if necessary.
Vespa LX 125 - 150 4T Euro 3
Troubleshooting
TROUBL - 35
Summary of Contents for LX 125 4T Euro 3
Page 1: ...SERVICE STATION MANUAL 633977 EN Vespa LX 125 150 4T Euro 3 ...
Page 4: ......
Page 6: ...INDEX OF TOPICS CHARACTERISTICS CHAR ...
Page 19: ...INDEX OF TOPICS TOOLING TOOL ...
Page 29: ...INDEX OF TOPICS MAINTENANCE MAIN ...
Page 34: ...INDEX OF TOPICS TROUBLESHOOTING TROUBL ...
Page 40: ...INDEX OF TOPICS ELECTRICAL SYSTEM ELE SYS ...
Page 69: ...INDEX OF TOPICS ENGINE FROM VEHICLE ENG VE ...
Page 73: ...INDEX OF TOPICS ENGINE ENG ...
Page 120: ...Conceptual diagrams Engine Vespa LX 125 150 4T Euro 3 ENG 120 ...
Page 145: ...INDEX OF TOPICS SUSPENSIONS SUSP ...
Page 160: ...INDEX OF TOPICS BRAKING SYSTEM BRAK SYS ...
Page 171: ...INDEX OF TOPICS CHASSIS CHAS ...
