Hesitation When Accelerating

[patrickt]

Originally Posted by zzmac

If the vacuum secondary spring is seated properly would this more than likely mean it needs a stronger spring (if it's the spring)?

That's one possibility, and that's the easiest answer (might not be the right one, but it's the easiest). There also could be a sticky mechanism involved, so that the vacuum mounts up and "pops" the secondaries open instead of smoothly and gradually opening them. It could also be a clog on the air bleeds over on the secondary side or any other transitioning orifice that's involved. I always instantly suspect a Holley has a clog even if the Holley just came out of the factory box because I've seen so many clogs and they can be caused by pretty small pieces of crap. It's probably not a clog, but I always suspect them nonetheless and clean them out good with the poisonous carb cleaner that works, not the watered down crap they sell in CA. Then I blow out the air bleeds, transition slots, idle mixture holes, all of that with about 30 psi of air from my compressor. Only then do I start thinking that it might be something else. The chart below is the spring rate for Holley vacuum secondaries. If you put the black spring in there, that's pretty much like having your secondaries tied down shut, so I bet the black spring would stop your bog. But you'd only have half a carb again. If you then walk up the chain until you find the spring that opens the secondaries the fastest, but without creating a bog, then that's the winner. BUT, if the problem is something else, like a sticky mechanism, then you're going to have to fix that to get everything to work just right.