25H.P. Johnson smokes whats wrong?

[piggy]

1999 25 H.P. Johnson on pontoon with T/T run it about level. Will run clean for a while then it will load up and smoke a while. Tryed adjusting carb (adjusting screw on top of carb that sets at an angle) did not make any difference. Was running half open then slower than half open again (checking night line river fishing for cat) but 1/2 open on longer runs didn't make any difference. Gas is mixed 50/1 very carfully. It starts right up, runs very good hot or cold. Spark plugs are QL77JC4. Tryed another set no difference. Only thing I can think of is rebuild carb. motor was bought from marine shop and was checked out. It did set about 6 month before used.

 

[5150abf]

Re: 25H.P. Johnson smokes whats wrong?

That motor can't be adjusted, it has fixxed jets, what you turned is a cover screw for the jet, put it back where it was.

They can be cleaned but not adjusted so I would undo whatever you have done so far and see how it runs then, with that cover loose it could be sucking air and making the engine run badly so fix that first.

Your post was a bit confusing,"ran half open"- the throttle was half on or the motor would only run half speed?

 

[kenmyfam]

Re: 25H.P. Johnson smokes whats wrong?

It's a 2 stroke. It will smoke. Does it leave a big white cloud behind you when it does this or just a little ???

 

[piggy]

Re: 25H.P. Johnson smokes whats wrong?

The smoke is burnt oil more than I've ever seen on a outboard and sometimes it runs good but just smokes and other times it also runs good with no smoke. Was I misinformed about the screw on top the carb. dealer told me to adjust this. I don't have shop manual for this motor yet. Sorry I wasn't clear but motor will go wide open or sounds about right. I meant motor was being run at 1/2 throttle. Only thing I did was move screw on top of carb no setting there made differance. What you are saying is that screw should be in tight or it will leak air? Thanks

 

[piggy]

Re: 25H.P. Johnson smokes whats wrong?

Again didn't make myself clear the adjustment as being on top of carb at an angle is needle valve slow speed adj. listed as part # 0335015. Tried moving it from about 1/2 turn open to about 4 turn open a 1/4 turn at a time and waited between each adjustment for time to adjust to new setting. Didn't seem to make a difference.