135 merc. OB jumps at no wake speed -1988

[Penn State Pirate]

New to this site today. Hello all.

I have a 135 Merc. outboard that runs great except when at no wake speeds. It jumps fast then slow. I am thinking it is the fuel filter which I have not checked yet. Any suggestions?

 

[wtwe2step]

Re: 135 merc. OB jumps at no wake speed -1988

New to this site today. Hello all.

I have a 135 Merc. outboard that runs great except when at no wake speeds. It jumps fast then slow. I am thinking it is the fuel filter which I have not checked yet. Any suggestions?

Two things I would do...... clean carbs.....rebuild fuel pump

 

[Chris1956]

Re: 135 merc. OB jumps at no wake speed -1988

That motor is a V6. It sounds like some cylinders are intermittently fouling at no wake speed, and then they fire. The cure is to adjust the idle mixture, leaning the affected cylinders somewhat, however, this only works if the carbs are clean. When was the last time they were cleaned?

 

[j_martin]

Re: 135 merc. OB jumps at no wake speed -1988

That motor is a V6. It sounds like some cylinders are intermittently fouling at no wake speed, and then they fire. The cure is to adjust the idle mixture, leaning the affected cylinders somewhat, however, this only works if the carbs are clean. When was the last time they were cleaned?

Some of them have a timing module on them called an idle stabilizer. If the idle speed gets too low, it advances the timing several degrees, speeding it up. If the idle is set close to the threshhold speed, it will tend to hunt for the right speed. (servo)

just a thought
John

 

[Penn State Pirate]

Re: 135 merc. OB jumps at no wake speed -1988

They have not been cleaned for a while. I do have the mixture a little rich.