1985 90hp Johnson v4.
It makes a rattling/ticking noise in the water. It is more noticeable if you are going kind of slow then accelerate a little (louder during the acceleration phase). Increases in frequency with increasing RPM (usually... see below for exception).
Took the cover (cowling) off while in the water and it definitely seems like it is coming from the flywheel or something attached to it. From what I could tell nothing was rubbing against it.
Ran it WOT for 7 or 8 miles. Stopped and did WOT again a few times. Each time once RPM hit about 4400 (maxes out 5000) the noise stopped and it ran like a top! Still seems to run good at lower RPM except the rattle, though maybe slightly rough (hard to tell being an old 2 stroke).
Got home, put it on the hose with and without the cover and no noise. Put my torque wrench at 100 ft lbs and the flywheel nut was/is tight. I have put on the hose previously recently (no rattle) and recently took off and put back on flywheel to make sure was tight.
The weird part is it only makes the noise in the water where there is back pressure.
Maybe flywheel magnet going bad? How do I tell if magnet is becoming delaminated (what to look for)? Maybe drive shaft problem like a bearing?
It makes a rattling/ticking noise in the water. It is more noticeable if you are going kind of slow then accelerate a little (louder during the acceleration phase). Increases in frequency with increasing RPM (usually... see below for exception).
Took the cover (cowling) off while in the water and it definitely seems like it is coming from the flywheel or something attached to it. From what I could tell nothing was rubbing against it.
Ran it WOT for 7 or 8 miles. Stopped and did WOT again a few times. Each time once RPM hit about 4400 (maxes out 5000) the noise stopped and it ran like a top! Still seems to run good at lower RPM except the rattle, though maybe slightly rough (hard to tell being an old 2 stroke).
Got home, put it on the hose with and without the cover and no noise. Put my torque wrench at 100 ft lbs and the flywheel nut was/is tight. I have put on the hose previously recently (no rattle) and recently took off and put back on flywheel to make sure was tight.
The weird part is it only makes the noise in the water where there is back pressure.
Maybe flywheel magnet going bad? How do I tell if magnet is becoming delaminated (what to look for)? Maybe drive shaft problem like a bearing?
Since it runs fine at WOT and not so good at lower RPM, you mich check the carbs. There are some small ports for low speed operation that may be clogged. Carbs on those old 2 strokes are simple to clean once you get them off the engine. 
