When the engine is cold, it will rev up some then the RPMs will slowly drop to idle. Then at random it will go up then down again. When the engine is warm, it will rev up to a point whether I give it some gas or not then very slowly drop but not all the way to idle. But aside from checking the usual things like the intake, is there anything else I can check? Has the original Speed carburetor and is a mostly stock setup except for a high compression head and mz65 clone. Engine has stock porting it has not been touched since new. Any help is appreciated.
Think I have an air leak but how can I locate it?
- Thread starter Rusty_Nail
- Start date
Carefully spray starter fluid around the gasket areas when the idle goes up... that will give you an idea where the problem is.
BE VERY CAREFULL!!! starter fluid is extremely flammable!
BE VERY CAREFULL!!! starter fluid is extremely flammable!
OK. I'll try that and I'll be very careful. I'm suspicious that its the intake gasket because when I took off the one that was already on the engine, it was the wrong shape. So I'm guessing when it was built at the factory the dumb asses put on the wrong gasket. I put a proper-fitting new one on with some red gasket maker to help ensure it seals. Once the gasket sealer is set, I'll Try starting it up to see if its fixed. One other question... could it possibly be one of the crank seals? I've seen some videos where they say that can cause an air leak but not sure how to check the crank seals for air leaks unless that's not very common?
OK guys, I think my suspicion was correct. After putting the new gasket in and giving the gasket maker about 6 hours to cure it fired right up and idles perfectly now. No more revving out.
