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Car SE6A hunting on idle

Posted: Wed Mar 13, 2019 10:21 pm
by james couper
Car starts OK, runs at 800 / 900 rpm when cold, take car for 30 min. run, car when hot starts to hunt rev,s starts to drop to 500 jumps back up to 900/1000, car running at 85 degrees, plugs are normal or standard ( light brown) do i need to check valve clearance. Adjusting idle speed makes no difference just drops or increases idle speed.
Carb 38 DGAS.

Car SE6A hunting on idle

Posted: Thu Mar 14, 2019 12:41 am
by TrevorG
Hi James, many experts here who should be able to help, I'm not one....but worth mentioning if carb is still on auto choke or converted to manual. If auto, is it fully opening when hot?

Car SE6A hunting on idle

Posted: Thu Mar 14, 2019 7:49 am
by peter freeman
Sounds to me like air getting into the carb base - check that the carb is not loose and that the gaskets and spacer are ok . Air gets sucked into the base and weakens the intake manifold mixture and the revs drop which reduces the pressure in the intake manifold so less air is sucked in so the mixture gets stronger and the revs increase again - and the cycle continues. Been there had that.