Carb Hesitation

Doesn't suck as much as you thought it did???R) R) Look here:http://www.tracyvette.com/enginevacuum.htmlMay provide a few clues.......

 

Researching manifold vacuum now. Here's something I just found: "If vacuum is steady at idle but lower than normal, the ignition or valve timing may be retarded. Low compression, an intake leak or tight valves also can cause low vacuum at idle."

I'll keep researching. And, I'll probably have to pull the valve covers.

 

Researching manifold vacuum now. Here's something I just found: "If vacuum is steady at idle but lower than normal, the ignition or valve timing may be retarded. Low compression, an intake leak or tight valves also can cause low vacuum at idle."

Could be the timing gear is in wrong position by a tooth or so.

Try this: Loosen the distributer hold-down bolt, ease the distributer in the direction of rotor travel. When you reach 20 inches of mercury, stop and tighten the hold-down bolt. Then reset the idle back down to 600 or 700 rpm, which ever you are more comfortable with.

 

Yes. I think I will try that. Basically setting the ignition timing using the vacuum gauge. Regarding the valve timing, I did replace the timing chain about 2 years ago. I'm pretty sure it's correct but It's hard to say for sure.
I may be able to set the idle mixture screws with the vacuum gauge also. Thanks.

 

did you get it running right?

 

Haven't made much progress - parked it outside so I could thaw out may truck in the garage.

Based on what I've learned it almost has to be an intake manifold vacuum leak. I'm going to try and borrow a propane setup to check it out.

My previous attempts at finding a vacuum leak were all done around the carb and not the intake manifold. So, I'm still "hopefull?" that I'll find a leak.