VESPA ET4 50, Workshop Manual

Page: 115 / 185

- Insert the diaphragm into the throttle valve.
- Insert the tapered pin together with the plastic
support and the contrast spring into the throttle
valve.
N.B.
PLACE THE SPRING PLASTIC SUPPORT WITH ITS TEETH
FACING THE INNER SIDE OF THE MEMBRANE TO BE
ABLE TO FIT THE LOWER END OF THE THROTTLE VALVE
SPRING.
- Fit the vacuum chamber cover with the 2 fixing
screws paying special attention to the spring.
Inspecting the automatic choke device
- Check that the automatic starter piston is not de-
formed or rusty.
- Check that the piston slides freely in its seating.
- Check that the piston sealing O-Ring is not de-
formed.
- The starter must be more or less functional de-
pending on the ambient temperature.
- Measure the protrusion of the piston as shown in
the figure and check its corresponding value.
- Make sure that the starter is adjusted for the am-
bient temperature.
Characteristic
Protrusion value
11 mm
ambient temperature
24° C
ET4 50
Engine
ENG - 115