popping back

trevo

Senior Member
Ford Men, when im travelling down hill and take my foot off the accelerator i hear a pop pop poping back through the tail pipes am I running a bit rich or maybe timing a bit retarded ideas would be appreciated thanks.
 
One thing the carburetor can't do is reduce the vaccuum caused by closing off the air supply at the air horn. That vaccuum sucks gas like it's going out of style, and with little oxygen to burn, the gas exits the cylinders unburned, picking up hot spots in the exhaust manifold to continue the burn in the exhaust system. Short answer: Shut up and listen to the music!
 
Thanks guys noticed it driving down a real steep windey hill I will check the vacuum side out otherwise turn the radio up cheers!
 
This was happening to me here with a new engine with dual carbs and someone here suggested enriching the idle circuit. I gave the idle mixture adjustment screws about another half turn and the popping went away for the most part.
 
Maybe someone blocked of the heat risers. The colder the weather gets they more you will hear the exhaust "back down", old hot rod term. G.M.
 
G.M.

Is there any harm to be had by this happening or just cool music of the flatheads !!!

The firing isn't violent enough to blow a muffler but it makes the engine firing cold and sometimes requires a little choking. After WWII we used 3" brass bomb shells for exhaust tips. You should have heard the "BARK" on cool nights. The heat risers warm the gas and it vaporizes better. G.M.
 
Some flatheads lovers get a big smile on there faces when they hear there exhaust pop (me) truly music to my ears. Proof that my flatty is alive and well. Lol
Happy Turkey Day!
Randy
 
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