hunting

[FelixFelix]

Hi Guys, this is my first post to the forum (or any forum for that matter), so hope you can help.
i have a 1983 E21 316 (1.8l) Automatic. i've owned the car for over a year and have had almost no trouble mechanically so far, just a reconditioned alternator fitted.
recently on starting the car the revs are very jumpy when idling, (i'm told this is called hunting), and acceleration is very jumpy when pulling away. when stationary in traffic the engine judders quite violently, less so if in park.
this seems to get better after the engine warms up for 20 minutes or so but does not disappear completely.

the last time this happened it was remedied by removing the air filter housing and giving the top of the carb a good clean, but the problem soon returned.
any suggestions on how to fix this permanently?

thanks

Felix

[Jeroen]

You may want to check if the thick rubber gasket at the carb base (between carb and intake manifold) is leaking. Spraying some WD40 or brake cleaner (beware with hot engine) around that area usually tells you... should be tight so if the engine responds there's a leak.

[FelixFelix]

Thanks Jeroen, i'll give it a go.
just to confirm; should I have the engine running when i spray some WD40 onto the rubber gasket?
are you suggesting that if the engine sounds better after the WD40 has been applied then the gasket is leaking and should be replaced?

thanks again

Felix

[nas80]

engine running yes.

That way when you spray wd40 to the bottom of the carb the engine note changes and you know you have an air leak.