slight backfire from carb on new engine rebuild
 

He guys i am hoping someone can help me. I have a new rebuilt mercruiser 260, 906 vortec heads and performer intake, thundervolt ignition new cap rotor, quadrajet carb, and a como cams marine 262 cam. Now heres the oroblem the boat fires up, i let it run for a sec try to idle it down and she stalls out and blows gas thru the carb. AAny ideas???? When its running it sounds strong no knocks nothing. Plug wites are good im stumped

With what you say the first thing I would check is the carb. My first thought is it's dumping fuel and it cant take it when the idle gets to low. Or it could be just the opposite and be fuel starved when the rpm gets to low.