the rear carb on my hemi, # 4432, has a serious stumble off idle due to a very weak pump shot from the accelerator pump squirter. I have checked the inlet check valve in the float bowl and its working properly. I have checked the accelerator pump linkage and height adjustment on the pump itself to make sure its correct. I have checked the brass discharge valve thats under the squirter to see that its not stuck in the closed position, and its not. I am not sure the shop that did the rebuild put the correct accelerator pump in this carb. I know that there are several different diameter pumps and different length pumps. How can I verify which is the correct one for this carb?? the pump bore looks like its in good condition. also, the passage from the pump well to the squirter is not blocked.


thanks

I would put my money on the problem being unrelated to the pump shot.

First be ABSALUTELY CERTAIN that you don't have a vacuum leak somewhere.

Next, check that your ignition is healthy and that your distributor vacuum advance is working properly.

Next be sure your fuel pump is good and filters aren't clogged.

Be sure your gas is clean! MANY fuel related issues these days with rust or varnish and junk in the old tanks making thier way to the carbs, as well as just modern fuel blends going bad faster than expected when sitting in a stored car.

If all else seems healthy check your float levels first, then reset your curb idle speed (the big air valve screw in the center of the carb base), then reset your idle mixture screws using a tach or a vacuum gauge shooting for peak numbers on each. See if that gets you anywhere.

the fuel is fresh, the tank , pump and lines are new. Everything is fresh. I have almost no fuel coming from the squirter nozzle. the pump on the front carb works fine. Engine vacuum is good.

thanks

Ok, well if you think there is a build issue I would go back to the company that did the rebuild and ask them to warranty the work. I assume they worked ok before?

*Did you check the float level?

This is the first time we have run these carbs. I checked the float level, and the driverside float was a little low. Factory setting says 7/32, which is .218, and it was at .300, so about .080 low. Dont think that is the problem because when I had the carb on the bench, I added some fuel to the bowls and rechecked the pump shot and it is almost non existent. pretty convinced its a problem with the pump bore or the wrong pump, ( length or diameter)

thanks

idle it for a minute to fill the bowl then take off the metering rods/carb top and take off the A/P plunger & push it down in the bore & see if you get a good squirt as the top does not need to be installed to check AP function. You can use a screwdriver around the inside perimeter of the leather cup between the cup and the spring to expand it a bit and there's several AP assemblies & they may have used the wrong one. I oil the leather to make it supple & conform to the bore better and take a better initial set. Not sure which is better leather or the neoprene type (ScottSmith Harms will know) but I'd get a new plunger & likely one of the eddy performer ones will fit and they are avail seperately

Thanks for your help, but I think I found the problem. I put the top of the front carb on the rear carb and now I have a pump shot. Looks like the hole in the top from the rear carb where the acc pump rides in is worn causing the pump to move sideways while pumping up and down. to double check this, I installed the top from the rear carb on the front carb, and the problem followed the top, no pump shot on the front carb, which worked fine before. Does anybody make a bushing for the pump hole in the carb top, or an oversize acc pump, or just change the carb top on the rear carb with one in better condition?

thanks

Which way is the acc pump link facing,should look like picture.Can't imagine the top being worn enough to have little or no pump shot.Also,some of the AFB pumps have a check ball in the bottom of the pump.

I was thinking the same thing Bill. If it actually is worn then maybe it was running with the s hook backwards for some time and caused undue wear on the hole? If that happened I'd reccomend just replacing the lid.

The s link was installed backwards when the carb came back from the rebuilder, so I corrected that, but I don`t know how long it ran like that. I did switch the acc pump from the front carb to the rear without changing the carb tops and still had no pump shot. It does not look like there is a place for a check ball at the bottom of the pump well in either the front or rear carb. There is what looks like a round metal plug at the bottom of each well. How can I tell if there is supposed to be a check ball in either carb in the pump well?

thanks for your assistance.

This is what I was refering to.

thanks, my acc pump is like the one on the right in your picture. Is that correct for my carb? looks like the one on the left should be used with a check ball and the one on the right without??

Either will work.If your pump is like the one on the right,the ball may not be seating.When the pump goes down,the ball goes up and seals the pump.Replacing the pump will probably solve your problem.

Are you referring to the ball that is in the inlet check valve that screws in from the float bowl??

Look at the pump on the right,look at the bottom,there is a check ball in the small hole in the middle of the pump.