carb backfire sorta

[ochretoe]

I recently had a duraspark II and a weber 32/36 put on my 74 bronco with a 200 and three on the tree. I had it done while I was out of town so I didn't do it myself. Now when I let off the gas I get a lot of popping from the engine. When I push in the clutch the popping stops. It did not do this befor the dizzy and carb swap. When just running it runs great. Any ideas?
Thanks
Steve

 

[pedal2themetal45]

Is it popping out the exhaust. If so I wouldn't worry about it. Might be needing a little adjustment of the carb/timming.. or maybe a new muffler.
Tim

 

[ochretoe]

I hear it out the exhaust. And with the top off I think I would hear it if it was a true backfire thru the carb. I'll check timming and plugs again. Could the carb just be a little lean or rich? Wich would make go pop pop pop pop when I go to slow down? (did you like my sound effects?)

 

[pedal2themetal45]

Not sure which way it would be.. Is it kind of like a truck off the gas going down hill using the compression to slow it down..POP,POP.POP.. Yes , NO??
might be the timming..
tim

 

[Anonymous]

After-firing thru the exhaust is usually a result of a rich mixture. Unburned fuel is getting ignited in the exhuast.
Doug

 

[ochretoe]

Not sure which way it would be.. Is it kind of like a truck off the gas going down hill using the compression to slow it down..POP,POP.POP.. Yes , NO??
might be the timming..
tim

Yes, it sounds a lot like that.

 

[pedal2themetal45]

I think 66fastback has the answer.. to rich.. see about rejetting the carb maybe might be to rich for the stock motor..
tim

 

[thinman56]

this happened to me and the cause was not enough ignition advance, soon as i got it up past 12 degrees initial the backfiring stopped.