sschulak

Guys,

I have a 65 mustang with a 289 and an edelbrock carburator, ive been having surging problems at part throttle, i tried a Holley carb and i still had the surging problem, i have a 3/4 racing cam which complicated things. Also when the engine is running at operational tempreature and i shut it off the engine makes a loud noise like stuff it slapping around.
I throw the timing light and i see the timing advancing forward and back with the surging. My timing is set right.

I tried retarding the time,
I tried replacing all the plugs,
I tried different carbs and fuel pumps and regulators all settings,
I tried setting the edelbrock 1 stage rich in power mode and part throttle
I tired replacing the distributor and coil
I tried spraying soaping water all over the engine looking for vacuum leaks,

Any more suggestions?
some one told me to check and see if my timming chain is loose and if the cam is loose,

Soaring

I'm thinking vacuum leak. Try some carburetor cleaner around the intake manifold and see if that smooths it out. If so, then the gasket on the intake needs replacing.

sschulak

I forgot to tell ya, i did rebuild my carb and sprayed it down the cleaner all over and out. The intake manifold gasket is what Im going after next. Is there a special gasget I need to buy or can I just use that silicone sealer crap?

ownsaglock

I agree.

If this doesnt pan out check your fuel filter. Mine did the same thing after a carb rebuild and the new filter was full of rust.Ended up changing the tank and cleaning the filter. All good after that.


EDIT:Throw the end gaskets out and use silicone. I used permatex black.

sschulak

I checked for vacuum leaks by using soapy water and blowing air down the pcv valve hose down the valve covers then down the carburator, I couldnt locat anytihng blowing bubbles,,,,

ideal_mustangs

If you spray carb cleaner around the intake and vaccum lines, the motor will change sounds when it picks up the carb cleaner.

Soaring

Vacuum sucks instead of blowing, so soapy water isn't going to have bubbles.

sschulak

the engine was off and i was using an air compressor blowing air down the valve covers via the pcv hole and then down the carb for the pcv hose connects to

highhilleer

I'm with the others, your soapy water method seems iffy. Try with the carb cleaner while the engine is running. If you have a vac leak the engine should speed up. I'd do this before changing the intake manifold gasket. I would also change the fuel filter, possibly with a clear one to see if you're getting crap in the gas.

You can check the tension of the timing chain by pulling the fuel pump and probing with a screw driver. There should be virtually no movement.

sschulak

good idea,,i will try that tonight