Can you help?

[Charlieboy]

...its starting to hurt my head.
Local bloke brings lammie round..Been threatening it for weeks, and I really dont need the hassle but said Id give it a going over. Li special 175, 20mm carb, scorpion pipe, electronic. Problem= bad starting after being run, carb flooding.
A few ppl have looked at it including a shop but cant suss it. It will start up no probs but when switched off and kicked over it floods. You can only start it by taking air rubber off but it makes no difference if the rubber is conected to the air filter at all. It spits back lots of juice for a small carb. The bloke is new to scooters and very panicky if he cant start it after running.
My first point of suspect was jetting and carb. Main was 118 (miles to big) so took it to 112 (about right) ..no difference. I know some will say main jet makes no difference but I disagree. Ive ran my lammie with big main jet and couldnt get it off tickover.
Anyway, sourced another carb to try as thought it may be worn..Made it worse. Wont even run with rubber on..Def to rich. Stock choke jet and idle jet..
Im running out of ideas.. float seems ok and needle valve is working.
Thinking along the lines of timing...Do you reckon if the timing was out that maybe as its not sparking in the right place all the unburnt fuel is getting pushed back out the carb? Im asking this cos im too f*cking lazy to go outside and check...Any other possiblities? Worn rings causeing flooding....help me :unsure:

[Worz]

Sounds like one of those nightmare ones but here's a few ideas.

Has the rubber tip on the carb needle got a ring worn into it? If it has then fuel could still be entering the carb when the engine has stopped and once the carbs full up there's only one place for it to go - the barrel.

The main jet only really has an effect when the throttle is 2 thrids or so open but it could possibly be too high a pilot jet.

The fact that the engine won't start when warm leads me to believe it could be an air leak. When the engine gets hot everything expands. Something could be letting air into the crankcase such as an oil seal, manifold or cylinder head. I wouldn't have thought worn rings as it would have the same probs when cold.

The timimg would also affect the starting when cold so i wouldn't think it was that. Still, stranger things have happened!

[Titch]

Piston in the wrong way round?

[Charlieboy]

Oh dear maybe it could be the pick up then..oops, I said it coulnd`t be as it fires ok just floods but I may end up with egg on me face here
Think I need to take it apart....It will run ok (supposedly) but startings the problem. I think it feels very boggy and wont tick over for long without blipping thr throttle..Just feels very rich but it cant be..
Ok, im out to check timing and spark then..

Titch, ive only ever seen a piston in the wrong way and that was me on my first vepsa, rebuilding it and didnt have a clue..Needless to say the piston lasted all of 5 seconds!!!

[Charlieboy]

Was of work today so decided to change the oil seals...........worked!!! Running like a dream now. Thanks for your help & advice Worzel.

[Worz]

Nice one mate. Glad you got it sorted and thanks for letting us know how you got on.