by Barringer
(Sointula, BC, Canada)
I took my boat out yesterday and returned today. The motor was basically running fine on way out, but the water was calm.
On the way home, the ocean was up to 10 foot waves, not something I enjoy running but the boat handled it.
I had good power and it would hold 4,100 revs nicely and could periodically run at 4,200. Recently tuned, fluids changed. Plugs changed not that long ago.
The engine ran smoothly but, unless I turned it off and restarted it, it would not put out more than 4100. And after turning it off, it ran smoothly at 5500 rpm and, within a few minutes settled back to 4100.
I couple years ago I spoked to a fellow that was replacing a device on his Yamaha 250 because he could not get higher rpms from his engine. I wish I got his name and number because it sounds like the same issue. I called to place that services Yamaha and they were not familiar with it. (Last summer I had fuel issues and they were able to keep the engine running at 5,000 for 60 min and it has not run since.)