Will not idle

[dkovacs]

I've recently restored my 70' 442 W30. The engine was totally rebuilt, including a rebuilt carb. The distributer is a 75 HEI. At first I was able to idle it to specs (old carb), but it didnt run right, so I replaced the carb, and now the lowest idle I can get is 1100. If I slow it down, it stalls out. I thought I had the idle jets adjusted to spec, but its impossible to tell. The timing is way out, because I can not idle it down to check. If I retard the timing - again it stalls (or backfires). Is there any ideas out there?

[MagicRat]

It sounds as if you have an intake maifold leak, a bad one. Look for a bad vaccuum line, or missing or mismatched carb base gasket. You might have to remove and reinstall the intake manifold.
If you had a shop rebuild the engine, they may be responsible for fixing it.

[dkovacs]

How do you find a vaccuum leak

[MagicRat]

Originally Posted by dkovacs

How do you find a vaccuum leak

You can spray WD40 around the gaskets that you think might be leaking, while the engine is running. If you spray over the leak, the idle speed will change. But really big leaks are audible. You can hear the sucking.
However, if the intake is leaking where the manifold meets the head from the inside of the engine, there is no way to detect that. If you eliminate all other leak sources, then thats it.

[dkovacs]

Thanks for the help, the carb was loose