Carb Mixture Screw Settings 85 60 HP Merc

[MadKatter]

Does anyone know the mixture screw setting for an 85 60HP Mercury 3cyl 2carb engine. This engine has the brown trim, I think I may be running too rich and wasting fuel.

 

[Laddies]

Re: Carb Mixture Screw Settings 85 60 HP Merc

The basic setting is 1 turn but the carbs must be adjusted in the water in gear to finish the adjustment, if they are overly lean the engine may be hard to start.

 

[hkeiner]

Re: Carb Mixture Screw Settings 85 60 HP Merc

You did not indicate your SN, so I am not sure of the design of your particular carbs, However, if they are like the carb in the attached JPG for a 60HP with SN 0G531301 and above, then the only adjustable jets (screws) on the carbs is for idle. The high speed jets are fixed. While adjusting idle jets is important for a smooth idling motor and good acceleration, they would not affect fuel usage much as most fuel is consumed at higher speeds. If you think that the motor is running too rich at higher speeds, your floats may need adjustment or replacement. It is unlikely that your fixed jet sizes are incorrect.

If your high speed jets are adjustable, please note that it has always been my understanding that too rich is better than too lean at high speeds. Too lean at high speeds may cause quick engine failure (pistons, etc.). It is also my understanding that idle jets set too lean are NOT similarly dangerous, just bad for good idle performance.

I hope I got this right and I am not misinforming you. Does anyone else agree or disagree with the above?

 

[MadKatter]

Re: Carb Mixture Screw Settings 85 60 HP Merc

Sorry about the serial number it is A109560 and the carbs look a little different. If you turn the mixture screws that are located on the front of the carbs on the right side running WOT it will shut off the fuel going through the carb jets. Any further assistance is greatly appreciated.