Cant get hole shot on Mercury 850 or 85hp

[snake91876]

I got a 70s mercury 850 that i have just rebuilt carbs and got new wires, plugs, fuel pump, etc.. and cannot bet a good hole shot. It bogs out when i give it the gas. I kept turning the screws out and got some hole shot i just cant gun it, it pulls up slow but does it a WOT plane. The boat is a fiberglass tri hull and 17 pitch prop on second trim notch. How far should i have to turn the idle air screws out. They are probably 2 to 3 turns out should i go further will it get better, ran out of daylight at the lake.

 

[Chris1956]

Re: Cant get hole shot on Mercury 850 or 85hp

You have likely turned the idle mixture screws out too far. You are on the right track however. Normally the correct setting is near 2 turns open, more or less. It sounds like you are real close. The top carb will usually need a bit more richening than the bottom carb.

Remember they have little or no effect on a motor spinning at 1200 RPM or more, so make sure the motor is idleing lower than 1100RPM.