Accelerator pump issues

[Blue71]

Stock 75 Bronco....New rebuilt 2150 motor craft carb. I noticed that it wasn't starting so I used a little starter fluid and it fired up. After setting overnight you have to prime the carb with fuel or starter fluid. I looked...and the accelerator pump arm was not actuating the dowel/rod that pushes in on the pump. That dowel won't push in at all......even by manually pushing on the pump arm. I also noticed for the second time that the accelerator pump was leaking from the weep hole under the arm. I pulled it apart and sure enough..another ripped acc pump diaphragm . Put it all back together with new diaphragm and tried it with no fuel in it and the dowel pushes in just fine when u push the throttle arm. After remounting it all...I tried it all again and when it gets fuel to it...it gets hard to push again. The throttle arm goes all the way back like it's supposed to. I pulled it all apart and replaced everything with a new kit. Cleaned all ports too. Still doing it.

Any ideas?

Thanks

Andy

 

[Slowleak]

It maybe that the discharge ports are clogged. Fuel is getting in but not out so it's blowing out your diaphragm. Try shooting some carb cleaner, or air, thru the discharge port. It's #2 in the picture below.

 

[jjjjjgrant]

check the spray nozzles in top of carb. they could be stopped up. I've had this happen twice. when you move the pump arm it should spray. if nozzles clogged up it won't spray and pump will have pressure therefor making it hard to operated manually. even one clogged nozzle will cause it, only one of mine was clogged.
CAUTION: when you take the nozzle assembly off, don't pump the accelerator pump unless you remove the little ball check down in the port. how do i know this you ask? well i forgot about the ball and it shot out of the hole, fortunately it didn't drop in carb, but i lost it.

 

[jckkys]

Like many things that involve many parts to insure good operation you may have to go through the whole circuit one part at a time. The smallest restriction are the nozzles in the booster venturi. They are only about .020" but you can still see through them, when they're open. If not a fine wire should clear it. The booster venturi hold down screw has a small pin in it used as a weight to help close the check ball that jjjjjgrant described. Don't loose any of these parts or you'll get a stumble when starting from a stop. The other passages are far larger. But a blast of carb cleaner in the discharge port will assure there's nothing blocking the passages. Do this with the carb off the engine for the reason Slowleak explained.