[Chiefly Fly'n]

I have a Yamaha 150 saltwater series and the power trim switch on the engine seems to develop a mind of it's own. Sometimes it will start trimming the engine down or up. In two instances it trimmed the unit out of the water while cruising at about 1200 rpm. Other times it seems to be stuck in the down mode, even though it has not been touched. I pulled into the drive the other evening and the trim was running when I got out of the car.

Time for a switch replacement????

 

[lewisfishing]

Sounds like a relay or two getting stuck...or weak, at least

 

[sundrop]

corroded switch, blast it through good with some pb blaster or wd40 and work it back and forth. I would plan on a replacement soon.

 

[Mechanic Bob]

You could just unhook the red wire from the switch on the motor housing. I assume you know that one is the problem and not the one at the helm.