S3 not starting

[rodders]

After taking my scooter out on even a short run e.g. 15mins. If I then leave it for 20/30 minutes, it won't start again.
Any ideas why? Probably something simple, but I'm certainly no mechanic.
I have a few spark plugs which I keep changing around as sometimes this helps.

[MK Monty]

Not a lot of info if its got a bellows on the carb remove it before you try and start it again and see if it has fuel sitting in the bellows. Other than that dont use any throttle as you kick it over a classic mistake made by a lot of folk, Choke are you useing it is it shutting off once turned off.

[rodders]

What are bellows?
I do use the choke and I'm pretty sure it cuts off with the tap. I never rev when statrting anymore since reading it on here somewhere.
My carb is a Dellorto SH1/20. Could it be something to do with the air/fuel mix?

[hullygully]

are you points or electronic?
are you using the correct grade plug with the correct gaps?
when was the last time the engine was serviced? ie de-coked, piston & ring gaps?
is it an old air filter?
how much oil are you putting in with the fuel?
etc............................................... give us some clues

[MK Monty]

You are running a standard carb, is it a standard LI150 or the like. if it is your carb should have a rubber bellows clamped to the open end of the carb going up to an air filter in a box. the spit back through the carb collects in the bellows and makes your restarting too rich so yes it can be mixture it can be choke it can be plug worn rings and a host of other things
We are all champing at the bit to help you but struggling with the little info you are providing, my crystal ball is not working very well today

[burnside]

Try starting without the fuel tap turned on and do not touch the throttle until it fires