hey, I built my satsuma, had originally twin carburetors, would run perfectly smooth no errors won't stall on idle. then recently I put new racing carburetors on, and the car made gunshot sounds until warm so I can tune them. but then, everytime I started up the satsuma from a cold engine the engine was running really lean till it warmed up, anyway I put the dual carbs back in and broken. pls, help. hope that info was useful.