Backfire when all 4 barrels open up

[73grande]

when i get on the throttle so much that all 4 barrels open it begins to sputter an backfire whats the problem i checked all the vacums hoses an none seem to be leaking an the plugs are good is it just a dirty card or what id please like to find out

 

[LMan]

check power valve or accel pump?

 

[12sec67]

usually backfire happens when it runs lean , your not getting the fuel through the carb. your float bowl may just be stuck.

 

[6t6stang]

I was getting same thing with my demon 625 carb and when I took the bowls
off the floats were not even in the housing so I was getting way too much gas.

I put the floats back in and now runs fine