I have fought tooth and nail for months an issue with low rpm at wot on a Merc 50 1985 2 stroke 4 cyl. I have dealt with the stator, trigger, carbs, switch box and everything else on the advice of outboard mechanics with no success. The engine would just bog down after about 2400 rpm.
The last thing I have done is pull the power head and replace the lower crank bearing and seals and the gaskets on top and bottom of the exhaust plate as well as the seals for the water tube. The exhaust tube was close to being completely blocked up by carbon deposits that had to be chiseled out bacause the deposits were so hard.
Long story short, I tried it out yesterday and now the engine hits 5100 rpms on my 24' pontoon. I don't know if the blockage or leaking gaskets/seals were the major problem. I believe a little of both since the water pressure on my guage has increased.
I post this simply as FYI if anyone else is experiencing the same problems and my issue would be something for others to consider.
This forum is really great and has helped me tremendously.
Have a nice day.
The last thing I have done is pull the power head and replace the lower crank bearing and seals and the gaskets on top and bottom of the exhaust plate as well as the seals for the water tube. The exhaust tube was close to being completely blocked up by carbon deposits that had to be chiseled out bacause the deposits were so hard.
Long story short, I tried it out yesterday and now the engine hits 5100 rpms on my 24' pontoon. I don't know if the blockage or leaking gaskets/seals were the major problem. I believe a little of both since the water pressure on my guage has increased.
I post this simply as FYI if anyone else is experiencing the same problems and my issue would be something for others to consider.
This forum is really great and has helped me tremendously.
Have a nice day.