"The 2bbl mercarb only has one
"The 2bbl mercarb only has one mixture screw. It's the one on the front, near the base.
Procedure is as Rod stated:
- Warm the engine.
- Put the throttle in neutral. If it won't idle in neutral, open the throttle a little to keep it running about 700rpm. Set the idle speed stop screw on the throttle linkage to match the throttle position. You should be able to pull the throttle back to neutral now.
- Adjust the idle mixture screw (either direction) to achieve the smoothest, highest RPM.
- Readjust the idle speed stop to get back to 700ish.
I've talked with folks that were pretty insistant about adjusting the idle speed with the boat in the water and in forward at idle. If it wants to bog down when you put it in gear at idle, just re-adjust the idle speed stop as Rod mentions, but at that point you should be done with idle mixture."