| : I'm hoping someone out there has a suggestion to help me with a problem i'm having. : My engine has recently been rebuilt. 30 over all the ususal
: balanced, adjustable tappet, hardened valve seats etc. : My problem is that I have been unable to get the motor to run
: smoothly. It starts easily, but requires that the fuels mixture
: be turned open 3-4 full turns. At that stage it will run and
: accelerate well. Any less and the engine, bucks and will
: not accelerate. : The timing is correct as far as I can see. I have tried 2
: Zenith carbs and 1 x aftermarket carb which runs the best of the three. I've checked the fuel flow which is adequate
: and have even blocked off the windshield wiper vacum. : The engine just seems to be running like it has a vacum leak.
: The manifold was milled and there were no apparent cracks.
: I've also retightened the manifold...all to no avail. : I really think it is carb or intake manifold related.
: On the road the car runs o k,does not overheat etc...
: but just will not run at idle. The air screw on the carb is currently 1/8 open. Opening the screw kills the motor. : I know that the engine is very tight..spec wise, and maybe this will improve after breakin... : I appreciate any help or advice. : Thanks in advance. : Ken Ken,
From the amount of fuel it takes to keep it runnung I too would look for a vacuum leak. Was the intake and exhaust manifolds milled together? If not one may not be seasling properly. You can also check for a leak by squirting oil over the gaskets and listening for a change in motor sound. I have also cracked a manifold when tightening it down. You may have to look very carefully or remove to locate the crack. Since it does not overheat I would think a valve is not stuck open and since several carbs give the same results I would not think a jet is clogged. I would continue to look for a vacuum leak around and in the intake manifold. Let is know what you find. Jim McPherson
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