Problem starter

Guys my 2 1/4 petrol with a webber carb starts fantastic when cold , if u walk away for 5 mins and restart again lovely , if you leave for like 15 -20 mins its a bugger to start agin and will flood if you use to much gas , has been liek it since i bought the 90 any ideas on the one? thanks in advance...

Confused, is it a 2.5 or 2.1/4 just 90’s have a 2.5 engine with a slightly different fuel system, it has a fuel return.
Does it have an electronic fuel pump?
Mechanical fuel pump, it sounds like the float in the carb could be at fault, its not uncommon for the float/needle or seat to become worn.
Is it a single or double choke carb?

I had a problem like that with one of those Webber carbs. I fixed it by overhauling the carb - new gaskets, needle valve, diaphram. I think the problem was caused by the needle valve. What was happening, was that the valve was still allowing fuel into the float chamber when it should not have - so the fuel level was too high. This was not a problem when the engine was running, but switching it off, leaving it for a few minutes and the extra fuel in the float chamber was gradually leaking into the inlet manifold causing the engine to flood. Warm the engine up, then take the air inlet pipe off the carb, open the throttle and see if fuel is dripping into the inlet manifold (ignore the fuel that squirts out as you open the throttle).