PIAGGIO Vespa LX 150 4T Euro 3 Service Station Manual page 143

Vespa LX 125 - 150 4T Euro 3
Engine
With the multimeter, check if the potentiometer is
working correctly by placing the probes on both
contactors indicated in the photograph .
With throttle valve completely closed, the resist-
ance value should be approx. 1.3 kOhm.
With throttle valve completely open, the resistance
value should be approx. 4.05 kOhm.
- Disconnect the fuel supply and the suction taking
pipe from the carburettor.
- Check that there are no fuel leaks between the
two tubes.
- Close the fuel outlet pipe.
- By means of the MITIVAC pump apply 0.1 bar of
suction to the tap.
- Make sure that the suction is kept stable and that
and that there are no fuel leaks.
- Reconnect the suction pipe to the manifold.
- Position the fuel pipe with the outlet at the point
of the tap.
- Turn the engine by using the starter for five sec-
onds with the carburettor at minimum.
- Take up the fuel by means of a graded burette.
N.B.
THE MEASUREMENT MAY BE FALSIFIED BY
THE INCORRECT NUMBER OF REVS OR BY
THE WRONG POSITION OF THE TUBE.. IN
THIS CASE, THE TENDENCY IS TO OBTAIN A
REDUCED FUEL FLOW RATE. THE SUCTION
OUTLET ON THE MANIFOLD HAS A SECTION
INTENTIONALLY REDUCED FOR THE PUR-
POSE OF ENHANCING THE SUCTION PULSA-
TION AND THEREBY GUARANTEE A CON-
STANT TAP FLOW RATE.
Specific tooling
020329Y MityVac vacuum-operated pump
Characteristic
Minimum flow rate
20 cc
ENG - 59