6 replies to this topic

[sheepy89]

its a 1986 austin mayfair with electronic ignition.

this has only been happening since yesterday afternoon on my way home from work but as soon as i stop and the revs hit idle speed i.e 1000rpm it just cuts out.

can anyone suggest anything that it may be?

cheers in advance

sean

[sheepy89]

anyone?

[MiniElliott]

Have you checked for any air leaks on the inlet side of the manifolds. Sounds like its getting too much air.

[dklawson]

+1 on the air leak.

Has anything (even seemingly unrelated things) been done to/with the car recently just prior to this problem appearing?

Even if absolutely nothing on the car has been worked on recently, look under the bonnet and inspect the intake manifold, carb, and hoses connected to them. Make sure no components are obviously loose. Inspect the hoses to make sure they are installed where they are supposed to be and that they have no splits or cracks. If you have a brake servo, pay particular attention to its hose to make sure it is attached and in good condition. If the servo hose is attached and intact, as a test consider temporarily removing the servo hose from the manifold and plugging that port on the manifold to see if the problem goes away.

[H.M.M.]

Could be the piston in the carb sticking, spring lost its pressure. or lack of oil in dashpot, these would all contribute to getting too much air. As the piston would stay up (open). Remove the dash pot plunger to check to oil level, the plunger should be stiffish to push in, if you over fill put a rag around the dashpot to stop access oil getting everywhere when you rev the engine. If the piston is sticking open, remove the dashpot and check the spring, should be about 4 inches long, check the movement on the piston, being carefully if you pull the piston out not to miss align the needle.

Edited by H.M.M., 20 July 2012 - 10:12 PM.

[crf150]

I have a hs4 single carb and it doesn't idle Properly with out the choke, but I think I might know what the problem is, does anyone know what the pipe is next to where the fuel goes in on the carb ? Because when I put my finger over the pipe or tube it makes the engine rev sort of high ish and when I take it off it goes back down. When it is sort of idling it pulses so it will be ticking over and then it would rev up and this would keep repeating.

Regards

[H.M.M.]

I have a hs4 single carb and it doesn't idle Properly with out the choke, but I think I might know what the problem is, does anyone know what the pipe is next to where the fuel goes in on the carb ? Because when I put my finger over the pipe or tube it makes the engine rev sort of high ish and when I take it off it goes back down. When it is sort of idling it pulses so it will be ticking over and then it would rev up and this would keep repeating.

Regards

That sound like the breather to the crank case.
There should be a piping running from the tappet chest or crank case breather to the carb.