Vacuum leak ??

[clazar]

I need to check for a vacuum leak on my 440+6. What are some ways to check for it???

The air-fuel screws have no effect when adjusting.


Chuck

 

[Banzaiii67]

No experience with a six pac.. but for a 4 bbl, a unlit Propane torch opened just enough to let propane escape and check in and around the base of the carbs and intake to see if the rpm rise and smooths out the engine..

How's the smell at idle, does it run rough?

 

[clazar]

No experience with a six pac.. but for a 4 bbl, a unlit Propane torch opened just enough to let propane escape and check in and around the base of the carbs and intake to see if the rpm rise and smooths out the engine..

How's the smell at idle, does it run rough?

Runs rough. the carbs have just been rebuilt. The carbs are set up a little hot, but definitely rich. I was trying to fine tune the mixture & no adjustment available. I think this is the first step to check.

 

[rscurtis]

A vacuum leak generally won't give you a rich idle. A rich idle with a vacuum leak will be a fast idle that you can't slow down. Being that we're talking about Holley's here, I would start looking for a leaking power valve(s).

 

[mopar 3 B]

Have all the throttle plates been checked for proper closer especially the center carb. If they are not closing you have no idle circuit.