Thanks Sean for your detailed reply. I'll certainly do that.

re: points plate question: I was trying to find a problem that wasn't there!

Another (daft) question, on a spare manifold, there is a very small hole on the underside that looks to be part of the casting.

But I can't work out what it is there for. Surely it would cause an air-leak?

I believe that is a drain hole, perhaps for water, although I've only ever seen petrol come out of there when fiddling around with the accelerator pump. Although it would cause an air leak, it is presumably a very precise diameter, and the effects of it are accounted for in jetting of the carburettor. That's my understanding at least.

I think it is there to let the surplus of petrol out incase there is too much petrol , so that the engine does not drown.

Correct

it does but as has been pointed out its compensated for in the jetting, it lets liquid petrol out which could otherwise cause a problem.

When spraying WD40/carb-cleaner/whatever around, trying to find an air leak, don't forget that this hole is there: It too can suck the chemical in and affect the idle speed. It helps to have a long straw on your spray-can, so that you can be accurate.

Have you had any luck mate?

I started a new thread (it seems to have vanished), because my car started doing something similar when i arrived at work. It wouldn't idle when stopping at lights etc on the way home, and i had to keep it on 3/4 choke or play with the throttle to keep it alive.

I left it for about 10 minutes when i got home, and it started and idled absolutely fine. After a 2 min drive i got the same problems.

Also, the carb is now making a weird sucking noise which I've only heard when playing with the throttle on the carb, but it seems to do this even when its trying to tick over. Is this a fuel/air issue or should I be looking elsewhere?

Last reply - sucking noise could be the pipe from carb to air filter.

Most likely culprit is a blocked idle jet, I'd think. It's the smallest one in the carb, and in my experience usually the first to block if there's any crud or varnish in the carb - perhaps why they made it so easy to get at?! The "hand over the carb" trick doesn't work for this one, so you'll have to take it out and clean it. We all know you shouldn't stick anything down a jet, but gentle use of a single strand of copper wire can be useful if the hole in the end is really gummed up.

The sucking noise is probably just your "induction roar", but it's worth checking the choke pull-off doofer works if it's still there. If it's not still there, is the hole blanked off?

re Joe's reply.

I have yet to strip the carb for a full look-see so I haven't found the fault yet.

I went down the quick route of substitution. (I'm lazy like that!)