The motor is a 2015 Mercury 150 HP 4-stroke. It started going full up on it’s own a couple of weekends ago. When I was called to the boat I used the throttle to trim it all the way down but it came all the way back up as soon as I released the switch. I then used the switch on the motor and it started working normally and wouldn’t duplicate. A few days later it did it again so I disconnected the trim switch on the throttle thinking it might be getting stuck. A few days later it did it again so I reconnected the switch on the throttle and took the boat for a drive. It would not trim up on it’s own but the boat was riding very tail heavy so I moved it to a lift and drained the pontoons. I took it for a second drive and still no joy on the uncommanded tilt so I disconnected both switches. Boat is still riding nose high so it didn’t bother me to disconnect the switches trimmed full down.
I am not sure what my next step should be. Couldn’t find a place where the hot wire would short to the up wire and, except for the first time, the system works normally when I check it. I pretty much eliminated the throttle switch since it was disconnected on the second occurrence. I can’t see a reason for a renter (or anyone else) to use the switch on the motor while running across the lake. Since this boat rides tail low, could the motor mounted switch be getting wet and short out?
I am not sure what my next step should be. Couldn’t find a place where the hot wire would short to the up wire and, except for the first time, the system works normally when I check it. I pretty much eliminated the throttle switch since it was disconnected on the second occurrence. I can’t see a reason for a renter (or anyone else) to use the switch on the motor while running across the lake. Since this boat rides tail low, could the motor mounted switch be getting wet and short out?