The pilot screw in one of my solex carbs is siezed in solid, I can get a pair of pliers on it for some good purchase, but I'm sure it'll break off before it frees.

It must be siezed, if it was cross threaded it would have broken off on the way in its that far in.

Any ideas on how to get it out without wrecking things?

Cheers.Pete.

is it brass in aloy?
if so vinegar in there will get rid of aloy corosion

Yes its brass in ally, I'll give that a go, cheers.

soke a rag in boilling water then rap it round the carb
leave it the the carb get warm then do it again has worked for me in the passed

Go the whole hog and boil it in vinegar on the stove for half an hour!

have you tried using an impact screwdriver?

Thanks for all the advice chaps, I think I used an element of each one:

Warmed it with a heat gun.....
Ran vinegar in via the drillings.
Tapped it with a small hammer to try and jar it free.
Finaly got a fraction of movement, then repeating the above increased the movement untill it came out with no damage.

Cheers.
Pete.