Just finished rebuilding a 3310 Holley 750. The accelerator pump seems to work intermittently. Not sure what's going on with it but, it's driving me nuts. One day it works fine, the next I get nothing from the squirters. The car starts and idles fine, it's just the off and on crap from the pump. What have I overlooked? And yes, the pump is adjusted according to the kit specs.

Holley newbie but what I'd do is take off the square pump cover with the 4 bolts & start with a visual. Not sure what Holleys use for a check valve like the ball and or tapered rod that carters use. look for anything stuck/missing/that dont look right

Maybe mess with the different cams that they come with. Contorts amount and how long fuel sprays.
If I'm off, somebody tell me and I'll delete this misinformation
Edit: power valve idea deleted

As RR said take it off and look everything over good. It sounds like you have a piece of trash aomewhere.

The power valve will have nothing to do with the pump. The cam controls the timing and duration of the pump shot.

Did you replace the check valve when you rebuilt it? It should have a small Orange umbrella visible with the accelerator pump removed. Alternatively it may be a small ball type check valve but that's an older design and not so typical. If either are present and look to be OK, check for debris.

Also, there are check valves under the squirter itself. Perhaps yours is stuck or plugged with debris. Remove the squirter, take a look and let us know what you come up with. Good Luck!

I just went through this on my Demon carb. There is a small umbrella looking rubber piece under your larger rubber diaphragm. The umbrella has a barbed extension. Be sure that the barb of the extension goes fully through the mounting hole. I had not fully engaged the barb, and I was having the same problem as you. The barb should go through the mounting hole and the umbrella should seat flat against the bottom of the housing. The umbrella acts like a check valve and so if it doesn’t seat correctly it will allow the accelerator pump shot pressure back into your carburetor bowl.

Unless the 3310 is a late production,it does not use the umbrella accelerator check valve.

It has the check ball in the pump. I'll pull the front bowl and check it out. I get a little squirt, but not much, so I'm thinking the squirters are clear. There is a little metal strap that's staked in under the check ball, if I bent it taking it out could it have too much space and be causing the ball not to push up into the hole?

There is never any need to remove the strap and check ball,it is not meant to be removed,any chance the pump diaphragm may be upside down

The original ball was badly corroded and had to be replaced. I've checked to make sure that the diaphragm is installed correctly. It's cupped for the spring. I'm still wondering if the strap is allowing too much space between the ball and the hole and not pushing the ball back in place on the pump shot.

The inlet check ball under the small metal strap needs to be free and move a little. It needs to drop down a tad to pull fuel in past it and then it needs to move back up a tad and seat so no fuel pushes out past it and all the fuel goes out the discharge passage. Also under the squiter will be a check ball or a check ball and a weight or a type of pointed weight to seal. It has to lift up to let fuel squirt past it when you push the pedal down and then it has to drop back down and seat so the pump pulls no air in past it when the pump refills. I would make sure both are free and seat good. Ron