carburator makes popping sound

[bigblue]

I own a stock 61 pickup, and while driviing one sunny day, I suddenly experienced a loud popping when ever I gave it gas. The noise seems to come right from the carburator area (single barrel Rochester). I have rebuilt the carb, as the insulator plate was cracked, but the popping is still there. What are some other possibilities????

I'm stumped.

Big bluex(
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[monster truck]

Need more information, does it do it all the time, only when the engine is cold and not at normal operating temperature? It could be in the timing, could be one lobe on the cam worn excessivly, this would cause popping back through the carb. all the time. Hope this helps you some.J.Corbett

 

[bigblue]

Thanks for the reply monster truck.

It does it hot and cold, but only when I give it gas. What about the vacuum advance on the distributor? How does that thing work anyhow? Would puting in a new distributor help?

Richard

 

[monster truck]

Could be in the dist. excessive wear, hows the dist. cap and rotor look? Any cracks or heavy deposits on the contacts? Sometimes we try to save ourselves some bucks by replacing parts till it runs ok, but we may spend more bucks than if we took the vehicle to a reputable repair shop that we can trust for some trouble shooting with all the proper equipment.The vacuum advance uses manifold vacuum to advance ignition timing as needed beyond the mechnical advance. I once had a 69 Impala, a lobe was worn on the cam and caused the engine to pop back through the carb. but I can't remember if it was all the time.The best I can remember it idled a little rough, popped back through the carb. during acceleration and at any speed on the highway. Also popped back through the carb. while racing the engine setting still. Sorry I can't be much more help without putting my hands on it.
J.Corbett

 

[bigblue]

Thank you very much for your help, I think I will look a little closer at the distributer and vaccuum advance. The distributer is quite worn.
Thanks again.

Bigblue

 

[dekoon]

It has been my experience that popping thru the carb under acceleration is a camshaft problem, worn lobes etc.
Don

 

[Craig]

Popping thru the carb is caused by only reasons.First off the timing is too far advanced.Second is the carb is too lean.It usually is the carb but always set timing first before messing with the carb mixture.