johnson 10R78M throttle response is crazy!

[johnnyrude78]

Took the boat out on the lake today and reached wide open throttle, heading across the lake, i turned the throttle to slow down and the engine stayed at full speed no matter where the handle was positioned. This really aggravates me when this happens. Does anybody have a clue as to whats wrong. This motor has been very slow to respond with the position of the throttle. This problem still exists even after a carb rebuild!

[johnnyrude78]

does this sound like a fuel delivery problem or a problem with the cdi system?

[Silvertip]

It sounds like a throttle linkage issue. Pull the cover and see how things are moving. As you operate the throttle the butterfly in the carb should move smoothly and linearly and the timing advance linkage should advance and retard the timing.

[johnnyrude78]

I forgot to tell you the motor doesn't do this at all when its on the stand with muffs! it responds very quick with no hesitation, but for some reason it only wants to act up in the water.

[nwcove]

do you run it a wot on muffs???? yikes?

[tomhath]

I forgot to tell you the motor doesn't do this at all when its on the stand with muffs! it responds very quick with no hesitation, but for some reason it only wants to act up in the water.

Yup, that's how they usually misbehave. It sounds like sticky linkage somewhere. Get some WD40 and spray everything that moves.

[johnnyrude78]

absolutely not, just idle and a few little revs at most!

[boobie]

You've got a prob in your throttle/spark timing linkage and you'll just have to look closer.