Re: wont idle
I would be willing to bet that the idle mixture is just a bit too lean. Either grime accumulation has restricted fuel flow a small amount or the last time it was not quite adjusted slightly rich enough.
With that second person in the boat the motor is another couple of inches deeper in the water. This increases exhaust back-pressure causing slightly less air-flow through the motor and carb, thus a tiny bit less fuel, just enough that it won't idle well and die.
Find the idle mixture screws on the side of each carb and give them a turn CCW just the width of the screwdriver bladeslot.
Test idle with the boat loaded and in gear. If it is better then adjust once more and re-test. Keep at it until you get the best possible idle speed in gear.
Now test acceleration. Your holeshot should be immediate and clean, no hint of hesitation, lean cough, or bog. If any of those then again turn out CCW another slot width and retest. Repeat until perfect.
All this is assuming that your carbs are clean, if it is suspected they are dirty, clean them spotless, then start adjustment from an initial one and one-half turn out from very lightly seated.
