Possible cure for hesitation

[knucklebuster]

If you are at a loss for a hesitation issue, look into this. I just picked through my 2100 2 barrel to solve a hesitation problem, and it turned out to be the orange rubber umbrella valve that is in the accelerator pump housing. Mine was torn a little, but I have heard people say it shouldnt matter because the internal check valve would keep accelerator pump pressure normal. Not true... that orange umbrella needs to be intact. After replacement, 0 hesitation.

[Ranchero50]

That little umbrella diaphram is the 'check ball' on a 2100.

Jamie

[HOWDY69]

Help me understand this. I assume (and we all know what that can do) that fuel has to be able to get into the accelerator pump through a one way valve and the nozzle may also be protected with a ball valve that works by gravity. On my 4150 I assumed the fuel came into the pump through the plastic umbrella valve at the bottom of the primary fuel bowl but is not suppose to be able to go back. That way when the pump is pressed the fuel goes up through the needle valve. I would think accelerator pumps would all need one valve for fuel entry and possible another check valve at the nozzle.

[knucklebuster]

You are right howdy... that is what I had to figure out the hard way. Makes perfect sense now that I think about it. The gravity check ball by the nozzle is irrellevent if that umbrella isn't controlling backpressure back into the float bowl.