carb fire

[71broncrollsport]

i was tuning my 302 and timed it to 6 degrees and then set my carb mixture it was running perfectly! as i let it idle it all of a sudden dies. i crank it and it wont start so figure its out of gas and fill it up. i fire it back up and its back to running like crap( popping, slow surging and then back firing out the carb and catching on fire) what can this be the carb? its a old 4160 holley and it sat for a long time, could the carb have failed?

 

[J&SBroncolvrs]

Holleys are known for the accelerator pump going when you get a backfire through the carb. I'd check that out, also is the 302 stock or have you hopped it up a bit? If the timing is too far advanced you will get a backfire through the carb. In my experience once you have changed the characteristics of an engine the stock timing setting can be no longer valid. After I build an engine I use a vacuum gauge to time it, makes it easy to get it dead on first try.

 

[71broncrollsport]

Holleys are known for the accelerator pump going when you get a backfire through the carb. I'd check that out, also is the 302 stock or have you hopped it up a bit? If the timing is too far advanced you will get a backfire through the carb. In my experience once you have changed the characteristics of an engine the stock timing setting can be no longer valid. After I build an engine I use a vacuum gauge to time it, makes it easy to get it dead on first try.

thanks it has simple bolt ons like headers elderbrock 4 barrel manifold msd coil and box and a air filter also it has all the emissions stuff off of it could that effect it?

 

[J&SBroncolvrs]

I was thinking more like a cam or something. Try retarding your timing by 2* and check your accelerator pump.

 

[71broncrollsport]

I was thinking more like a cam or something. Try retarding your timing by 2* and check your accelerator pump.

ok thanks i figured out that i forgot to disconect the vaccuum advance so ill retry my timing