vespa fly wheel overdrive!

[henro]

hi all,

I have been out on my vespa over the weekend and noticed that once the engine is warmed up and i turn it off to kick it again the engine seems to take off on its own.

Once warmed up and i kick it, it starts first time kicks over and then seems to take off without my turning the throttle. It then stays at this speed.

Is this just the engine warming up and getting up to speed? I am just looking for confirmation on this as I have seen no "warning signs"- ie smells of burning or engine over-heating.

As always any information much appreciated for this vespa novice!

Cheers

Henro

[qapmoc]

This sounds like what you mean is the engine runs slow when cold and faster when hot??

Provided the speed increase is only small this is probably normal behaviour for a small two stroke engine.

[stanleyman]

This could either be the spring return not working on the carb/throttle or more likely if the engine settles down after a while, it's fuel drained into or built up in the crankcase, its own little reserve is feeding the engine and as it is already in the engine you can't control it. Very common on two strokes, turn off the fuel whenever you stop and get a new needle valve. You may also have a blocked crank drain if you have one that is.

[henro]

hi,

thanks for that. I shall turn the fuel tap off when not in use and see what happens.

is the fuel/needle valve hard to replace for a novice like me? and how do i check for the broken spring on the throttle cable?

oh and the crank drain...

cheers

henro

[TheBoyWonder]

Hi Henro, is this a vespa PK? it may be an air leak in the carb. when it runs quick, try pulling the choke out, and if it dies down, then it most likely is, I had one on mine.