S&S SUPER B backfire thru carb

[frankovy]

Hard starting and backfire thru carb. I have to turn the air fuel idle mixture screw down two and a half full turns before I can start 62 pan. Then the engine revs like mad until I can turn it back. After I get it started and warm it starts a lot easier until the next day. What should i look for?
please reply

[57pan]

Well, I don't know anything about the Super B carb, but backfiring thru the carb while trying to start it usually means I have to retard the spark a little more because it is firing before the intake valve is fully closed.

But there may be other things going on too - have you checked for the evil manifold leak???

[frankovy]

WOULD A MANIFOLD LEAK EFFECT THE DRIVABILITY ONCE IT STARTS
AND IS WARM THERE IS NO PROBLEM STARTING AFTER THAT, UNTIL
IT SITS OVERNIGHT. EIGHT TO TEN HOURS.

[58flh]

remember s&s super b has an enrichment-valve rather than a choke, I use to run a super b on my 69 sporty, & ran into the same problem you have! What i did was take the carb apart ,you cant go wrong here theres no parts to lose ,simple design. Now take the enrichment valve out, inspect for wear, most likely you will find slop in the shaft. Buy a new valve i think i paid$7.00 for mine 6yrs. ago! After you install your problem should begone! Also since a super b doesnt have an accelerator pump ( heres a cool trick i did, find the airbleed on the body of the carb. Drill it out & screw a 120 mainjet in it. You will be able to crack the throttle like it has an accel.pump.) If it still backfires thru the carb. check-timing if its spot-on then the olny other problem it could be is a worn-lifter or camlobe. Good-luck 58flh