Modern Vespa

Hi , I'm new to this but was hoping someone may be able to help . I have a 2008 Vespa S502t which for a long time has been VERY difficult to start , but once running is fine. Recently tho after leaving under cover for 2/3 weeks there has been literally pints and pints of fuel blowing out the exhaust before it finally starts . I filled the tank up and it appears to have emptied itself over the last 3 weeks although no evidence of fuel on the ground it's all in the exhaust !!
Anybody able to help with any ideas or suggestions ?

Looks like your fuel tap and carb float needle are in need of replacement. Both should close when parked. Somethings holding them open allowing gravity to move fuel to the lowest spot (your exhaust).

pull the exhaust and drain it. this is super fun, expect to spill it all over yourself and everywhere in close proximity.

replace the tap. check the float and needle, probably replace the needle. run new fuel and vacuum lines while you're there. snap in a fresh plug and away you go.

Cheers ,thanks for the advice , appears to point toward the float from what's being said . This Vespa doesn't have a fuel tap on at all , think with it being more modern .
Dunno if I trust myself to dismantle a carb and replace bits or just buy a complete replacement
for the tips

Ah thanks really appreciate the reply, this Vespa doesn't actually have a fuel tap on it but thinking maybe the float sticking in the carb is a possibility .Don't know if that's an easy fix or maybe a total new carb to cover all bases is better option

if it doesn't have a tap, that's something you should consider rectifying. either install a tap or stab in a shut off valve in the fuel supply line.

personally, I would try and clean and rebuild what you have. new carbs are spotty quality. and if you have to wind up there with a new one, splash the cash and buy name brand. and get a 17.5 over the stock size.

Many thanks for the info , the current one is a Dellorto PHVA 17.5 and they seem to be available for around £100 , May be easier to fit that and save labour costs on trying to fix the existing , just gotta figure if I dare attempt it myself !!