hi, my 82 polo has a problem, its a 1.3 carb (pierburg i think)

when its idling it goes up and down, its very lumpy, almost cutting out and after a few minutes it does actually cut out.

also when dipping the clutch on the move and when pulling up to junctions it cuts out. restarts fine though.

I've so far replaced:

carb-inlet gasket

plugs

leads

dizzy cap

fuel filter

had the carb cleaned out

to fit this weekend:

rotor arm

new vacuum hoses

new breather hose from airbox to crankcase?

condensor

inlet gasket

rocker gasket

anything else worth trying? I'm going to strip the inlet mani off and clean it out and replace gaskets etc, should i be looking at anything else? coil etc? or does this sound like an air leak or something?

What you describe indicates possible automatic choke issues, so many folk have this problem as the pierburgs tend to get neglected. I think you are making the right steps eliminating carb gasket problems.

On here somewhere(spend some time on the search engine)I'm sure there is something on adjusting the choke unit where something like a hammer gets worn and needs adjusting. The reason I'm not giving you a solution is that I changed my carb to weber before I ever got my head round the problem. The fact you have done some good sensible servicing so far indicates to me that you'll get this figured out.

There are folk on here who will know so be patient...

Have you checked the points gap is OK? This will close up with wear and make the car run badly.

i changed the plugs, where is the points?

car is manual choke :)

changed the vacuum hoses and no difference. :(

I've really no idea what I'm doing here haha

This post might help...

but cutting out might just be too low idle speed screw. I'd expect 800 to 950 rpm.

Edited 16 October, 200817 yr by dvderlm

does sound like the idle is too low, could be the vaccum advance, thats the silver flying saucer type thing on the dizzy, when its idling pull the hose off that and see if it changes, you should be able to stick your finger over the end of the pipe and feel it sucking then when you unplug that hose it should die right off to almost stalling. could try raising the idle speed on the carb, the screw for that is on the left hand side and should have a plastic tube over it then see if unplugging that hose makes any difference. I'd say that was the most likely suspect.

If it was an airleak thats mainly due to the rubber mount under the carb being perished, I always use some blue hylomar around the gasket to stick it down just to make sure there are no leaks. with it running try spraying some carb cleaner or WD40 around the base of the carb see if it picks up slightly thats a sure sign there is an air leak. but my moneys on the vacuum advance at the moment as you seem to have ruled out most other things.