Vacuum Leak 350/350 Question

[54blackhornet]

Trying to get a Qjet dialed in, while adjusting idle mixture screws I notice no change in idle up or down ? Started looking for vacuumed leak but no luck. Can any one suggest a way to eliminate things that I might have overlooked ? Truck has no power brakes, but still have charcoal canister hooked up. Should I block off trans modulator valve also. Thanks guys....

[hugger6933]

Have you tried spaying carb cleaner around the motor and gasket areas to see if at any time the engine will rev higher than the idle while spraying you have found the leak. for instance your going around the intake and go to the carb pad, and the motor revs, I would say you have a bad carb to intake gasket.
Now if you have put a Edelbrock or Carter type carb on a spread bore type or even a dual type intake, sometimes they require a special thicker intake to carb gasket to prevent vacuum leaks. You can find the real easy at Jeg's or Summit or even read about them in the online owners Manuel from Edelbrock about setting up their carb. Jim

[outdoorsman310]

sometimes the qjets have a worn out primary throttle shaft and have a vacuum leak around there. Just something to check.
Also dont jam the idle screws down if you bottom them out.

[geezer#99]

What's your initial timing?
Where's your vac advance plugged to?
You're likely idling on the power circuit!
Without enough timing you need to open the throttle more at idle and have uncovered the transition slots.

[54blackhornet]

Thanks guys for the help ! Qjet was rebuilt by the Carb Shop in Calf. Throttle shaft was rebushed and dynoed. Bought a new base gasket from NAPA for a 71 model Qjet. Just can't get it to run right at all ? Went to a Edelbrock but was not happy with that stupid adapter needed to mount it on stock intake. I don't want to give up.....

[geezer#99]

What exactly is it doing and when?
And maybe answer the timing question.

[54blackhornet]

I got it to idle ok , Little high, but when you give it a little gas it just falls on its face ?

[geezer#99]

And when does it to that?
When warmed up completely after a 20 minute drive or a couple minutes after you start it and the choke just opened?
And once more, what's your timing set up?