Hey guys I have a problem with the accelerator pump on a 72 smallblock thermoquad. The problem is it doesn't work at the initial crack of the throttle. I took it apart, the pump had a small crack in it, put a new check valve, pump, line, and needle in it. Put it back together, same issue.
It looks to me the spring in the accelerator pump is what actually activates the pump when the throttle is cracked. I don't have another one. Anybody know if there are stronger ones available, the rebuild kits I have don't come with one.
Any books avail to help a noob on these things?
Thanks guys

The spring for that should be cone shaped.

Check the linkage. Sometimes you need to adjust the pump rod(bend it) so the pump is positioned high when the throttle is in the idle position. I would also check the actuator mechanism on the throttle shaft. If you have an untouched carb to compare yours to that may help track down the problem.

The pump is alittle over 1/2" up in idle position, when you crack the throttle, it doesn't move until it is forced to move by the linkage on the throttle shaft, which is over 1/2throttle. I need it to move instantly when hitting the throttle.

It sounds like the rod it too short (too much bend in it).

I just rebuilt the thermoquad on my 74 400 and have kinda the same issue with a slight hesitation during part throttle. Would that mean I need more or less travel on the acc. pump?

If I take the rod out of the equation, I have to give the pump alittle help then it sucks down. I really think I need a stronger spring

I will try lengthening the rod to see if it helps.

The pump should not need any help to move. There is a problem with the spring or the pump is somehow getting caught.

Can you stretch the spring Brian?

I did alittle bit. It has rust on it, and the pump had a crack in it. I think its just plum worn out. I also tried getting ahold of the guy that built it too...

I have one built for a SS car, but under strict instructions not to take the top off. Afraid I might need alittle more fuel..