Holley 94 throttle plate question

Can't seem to get my throttle plates to seal quite right. On one secondary, I put my hand on it at idle and I barely feel any vacuum at all. On the other, it's quite substantial. Seems like it would be easy, but Im not having any luck. Anybody got any secrets they would like to share?

Crease
Barons So Tex

 

Sounds like one or both the butterflies isn't centered in the bore?
re-stake the threads after you adjust them.

 

I'm having the same problem on my flathead. The rear carb sucks like Honda's at the dragstrip while the front one is more like a nine-sec street car at the same strip. Which one do want to be driving?

 

Been away for 3 days.

Here are a couple of areas to check that all contribute to vacuum loss:

1. Rust pitted casting
2. Throttle plate corrosion at the ends from sitting with water on them. See above for matching problem.
3. Worn throttle shaft bore/bushing causing poor fitting rod.
3. Ive even seen some try and install the plates backward and then file to fit!
4. Installing flathead plates on a Y Block base.

Hold the carb up to a bright light, with the plates closed there should be just a very tiny sliver of light all around.

Shaft bushings, oversize shafts, plates are all available new. Sometimes it takes a few spare carbs to get a good one together.

Also in the base of Y Block 94 carbs is a spark arrestor. This often is corroded away internally. Best bet is to remove and plug.

Without a Unisyn or similar tool it is often a real chore to adjust multiple 94's. However the first step should be a vacuum gauge.

 

Thanks for that very useful info !
- I've got four "mix and match" 94's on my Y-Block . They're on a dual 4 barrel intake with an adapter I made. The front two carbs feed the front 4 cylinders, the others, the back four. The centre two suck at wildly different rates - Guess I should have figured as much using junky carbs. At least now I've got some ideas how to cure it.

 

Reason #3 286, your hired!

Looked like they were closing off nicely, but when I compared it to another carb it wasn't working quite the same. Sure enough, you can put them suckers in backwards.
Guess if I want something done right I've gotta hire someone else to do it. Oh well, learned sumthin new, that's what it's all about.

Thanks for the input guys!

 

Hi Mate,

I had this issue as well - throttle blades in backwards and caused all kinds of trouble.

D