My 1998 Johnson 150 Oceanrunner has always been trouble free. Within the last month the engine tilt has raised the engine on its own 3 or 4 times. My son took the boat out one day and on returning with the engine up I chastised him for driving it back that way. Since then I have lowered it onto the transom saver and came back later and found it up. This past weekend I was under the boat patching a chip in the gel coat when the engine just raised up in front of my eyes. I would assume some possibilities are a short in either the rocker switch on the engine or the switch on the throttle lever but unsure the best way to proceed. I guess I could try disconnecting one switch at a time and see if happens again over a period of time. Is there some electronic part that is involved in any of this? Ever happened to anybody else?