holly 600 vac sec problem

[marq]

Hi all i'm running a holly 600 vac sec on my sbc,now it starts real nice revs real nice until it goes in gear and you try to pull away the engine just dies.Now the other thing is that even with both fuel /air mixture screws full in it will tick over aint supposed too so it must be getting fuel elsewhere which i need to stop.When i pull away theres no rich smell and everything seems dandy ceptin it stalls............ideas are requested and will be well received...........Marq

[SimonSez]

Are you gettting a good squirt from the accelerator pump ?

[Hot Rod To Hell]

You have a Vacuum leak. The Idle screws control AIR flow, not FUEL flow. If it'll run with those in all the way it's getting AIR from somewhere else.

[Mojo]

I spent $30 on a BG rebuild kit for mine, washed and blew it out real good, and put it back together real careful. Stupid thing ran worse than before. It was perculating like crazy. I got pissed and blew $300 on a Eldy AFB. I set the idle and choke, and it was perfect. Moral of the story: I friggin HATE holleys. Fine to play with if you like pulling off the road 2 or 3 times a day to adjust something else trying to make it run right.

Pull it off the motor, lay a straight edge along the base... I bet it's warped. They seem to like to do that.

[colorado51]

Yea, sounds like it could be a vacuum leak.

Make sure the base plate hasn’t been warped from over tightening.

Maybe check the accelerator pump adjustment (that cam thingy).

[OldCarPilot]

And just to add... If its an older holley you know that the power vavle is very susceptible to breaking if there is ANY kind of backfire. There newer ones have taken care of this, and you can get something from holley to retrofit the older ones. If it is an older one you might want to try swapping power valves, or just have one on hand.