Is my carb. TOO big???

[73MACH]

351 cleveland with a new last year holley 750 vac. secondaries. Very mild cam. The problem I'm having is that the secondaries are not opening at all! Wondering if I'm not pulling enough vacuum. Bought quick change kit, tried that. Nothing. Power valve is good, secondaries work with seperate vacuum line on,(plunger moves up and down). Diaphram is good. Plenty of vacuum.
I called Holley and explained my problem. They had me ship it back and they wet flow tested it and whatever else they do, sent it back and said it was ok.
Well, it's not ok and it really starting to p*ss me off!:flipoff2:

Anybody have any ideas??

Thanks for the help.

[Prince Valiant]

So even with the lightest spring, you're secondaries aren't opening?

How are you verifying this? By just a quickly popping the throttle open by hand? Or just going by ear?

[DR.FORD]

Yes, I know what the problem is.
Bring me the carb.

[73MACH]

Ok, Jim. I'll swing it down tomorrow. What time and where is the shop again? I talked to you about this problem last year but Holley INSISTED that I send it in to them. Anyways, I should've just brought it to you to begin with.:chair:

Thanks again!

Jason

[73MACH]

So even with the lightest spring, you're secondaries aren't opening?

How are you verifying this? By just a quickly popping the throttle open by hand? Or just going by ear?

Prince, there is a little paper clip trickk you can do to find out.

[Prince Valiant]

Prince, there is a little paper clip trickk you can do to find out.What's this trick? Never heard of it, lol.

It's got to be better than what we do...just pop the hood up, put someone laying over the engine/carb, and drive with our heads out the window. It's scary. :goof

[73MACH]

LMAO!! You put a paperclip on the rod that comes out of the bottom of the spring housing. Then you take it for a drive. You drive it like a car is supposed to be driven for a couple miles, pull over and look at the clip. If your secondaries are opening, the paperclip will have moved to about halfway or so down the rod. If they are not opening, the clip will still be up tight to the spring housing.


WAAAAYYYYYYYYYYY less scarey!!! lol

[Prince Valiant]

Yeah...I jest, lol.

The first thing I'd probably do would be to remove the check ball in the diaphragm housing and see if it's opening then...it'll probably start opening too quickly with the lightest spring in there, so you might want to go back to the bigger spring (i forget the colors...) first and then see if it's opening...then start going down till you get a stumble then back up one.

I learned several things new today (thanks for the paper clip trick)...I also looked into a quadrajet for the first time today thanks to dr. buick, lol. There weren't gremlins in there like I thought....

[73MACH]

lol, no problem.