exhaust popping

[my425E1979]

hey fellas, thought i'd pose this one to the masters... so i recently replaced the floats in my carburetors and upon reassembly, aside from astonishment that the dang thing ran at all, noticed a slight popping sound coming from the left exhaust pipe.. now this is the vacuum side of my two carburetors.. and i noticed when i had them apart that the float pin on this same side did not have the same resistance as the other side did.. in other words, the pin would depress slightly from the weight of the float tab.. would this effect fuel flow on the left side carb at all..? or what's more, be responsible for the pop i am hearing?? thanks in advance for your input.;

[Guest]

Popping usually is related to a lean condition but can also be caused by a bad exhaust gasket or bad o-rings on the intake manifold. If you measured the float properly it shouldn't be a problem but I'm not sure if I understand your question about the float

[my425E1979]

chef, when i replaced the floats, the book called for between 25.5 and 27.5 float height.. i just eyeballed them to about 27mm... i don't think this would have much to do with the popping because the other cylinder sounds fine.. but like i said, that one float pin would not spring up to full height.. anyway, if the pop is simply a lean mixture, which way on the air screws?? my common sense would say turning out allows more air=lean, and screwing in cuts down the air flow=rich, but i remember reading somewhere that the opposite is true... what's your take on this>8-[

[Jethro]

The critical part of the float jet needle is that it isn't worn with a ridge or corrosion. The fuel should shut off ok, the springs in the needles aren't always perfect. That shouldn't cause popping. How did you check your float heights? I use a clear tube attached to the bowl drain to check the level.

As said before, popping can be the result of to lean a mixture. But also a very rich condition can cause popping also, as can exhasut gaskets, manifold boots, etc. If the popping is really present, the mixture screws won't help. Take plug reads at 1/8, 1/4 and half throttle and try to diagnose with what you find.