Ok..... I have changed the plugs, changed the cap and rotor checked the timing and it hasn't moved nore have I ever adjusted it. I still have a miss under load and the car likes to backfire through the carb. I thought it was too lean.... so I gave it a turn then drove it..... I had it so rich it fouled the plugs and still pops through the carb. I changed the plugs again. Now what. Think the carb has taken a shit? What could I be missing? I drained the Tank to make sure it wasn't bad gas and put 93 octane in it and still it pops. Drop your 2 cents.

 

I should have stated that the carb is a Race Demon RS 775 cfm. If that matters.

 

bad valve or one not seating ??..wiped cam lobe?? need more details . or plug wires misrouted

 

Mine was doing the same thing. Turned out that i did not hook up the brake booster, which caused a big ass vacuum leak.

 

floats stuck open?

 

Welcome to the "Demon Carb" club..

I have a Demon 850 that likes to do that also. They are a bitch to tune bro..
Are you using a carb spacer? If so, try removing it.. Mine was working great until I placed that damn spacer under it. (NOS Plate) You will have to play with all 4 cornering adjustments...

I feel your pain!!! Good luck.

 

It just started doing it, new cam and new valves. The spacer under the carb has been there since the rebuild. I will check my vaccum lines tomorrow.

 

had the same problem on our truck which has demon 850 in it, check the power valve, and then check timing it could be 180 out as scott said

 

But it all just started doing it...... I will check the power valve in the carb. What are other symptoms of 180 timing being off?