Mike Hucke

[MikeHucke]

Just purchased a Boston Whaler super sport 150 with a 2010 Mercury 60 hp Bigfoot engine ...the boat looks to be in perfect condition as well as the engine and has been garaged.... The engine starts beautifully runs clean and functions perfectly EXCEPT for one thing...there is a trouble spot when the boat is running between 1300 and 1400 rpm's where the engine begins to rev and cycle up and down... this malfunction (rev rev rev) will continue until you either increase or decrease the throttle out of that particular rpm range and then the engine will return to running smoothly....The boat does not sputter or smoke or misfire or stall but definitely something is not right. It happens whether it's being operated in the water or out of the water and whether it's in gear or out of gear.... any suggestions or explanations as to what could be causing this would be greatly appreciated...thank you in advance!

 

[Mohawkmtrs]

It's called "hunting", a lean mixture condition and yours is at that transition point between low and high speed.

It can be caused by a dirty carburetor, too lean of a setting of the idle (low speed) mixture screw, among others.

Easiest thing to do is open (turn counter-clockwise) the idle mixture screw 1/8th turn and add some SeaFoam to the fuel tank.

 

[MH Hawker]

it wont hurt to lube the timing advance plate

 

[solutions]

I have a 2010 sport and the hunting got to the the point the engine would stall. Not that I would advise to start at the injectors but that is what took to rectify my driveability issue. They can be cleaned.