Engine stalling!

My series 3, 2.25 petrol has been running fine up until yesterday and today.

It starts fine, runs well with choke on, but as soon as I push choke in, it cuts out, even when its warmed up..
If I pull choke out again it starts fine again, and so on.

It has a webber carb on it.

Any ideas?

Main jet blocked, needs cleaning out, **** easy job to do.

Can that be done with carb in place?

pegibson said:

Can that be done with carb in place?

Click to expand...

Yes! but you'll have to take the gear box out, and take all the wheels off and empty the ashtray, and top up the clack valve locator, then it's a **** easy job.

Yes you can, please don't. You're bound to drop something down the air inlet or into the oily crud at the bottom of the engine bay and it'll be much easier to remove the old gasket when it's off. You might be lucky enough to get the top off without knackering the gasket but it's unlikely in my experience.
Pop it off, clean the outside with a stiff toothbrush and some carb cleaner, strip, clean all the bits with the rest of the carb cleaner, find somewhere CLEAN and reassemble.

UPDATE

Stripped carb down, sprayed thru with carb cleaner, put back together. works fine now..