1985 Mercruiser 170, 2 barrel MerCarb:<br />runs great WOT... runs great when I first start it, choke. Warms up OK and then... idle varies from stalling to 2000 rpm, no real control... I had to backout the idle mixture screw 3 1/2 turns to keep it from stalling.<br /><br />I just put a new float in the carb but, wasn't sure which way the spring went in (in front or, behind the carb fuel filter)?<br />Timing is at 4 degrees per latest service bulletin I could find.