I have a 1992 70hp Johnson that has started trimming itself up without anyone being near the boat. I am thinking that it is either the relays sticking or a short somewhere. Does anyone have an idea where to start troubleshooting and how to do it?
Gene
most often it is the cowl mounted switch that causes the issue - water in the switch. could be a relay. not too difficult to troubleshoot. swap the relays and see if the problem moves. if not, switches or harness.
I would check the bow mounted switch if you have one. I see it all the time.
If you can duplicate the problem, unplug the switches one at a time. When the issue stops, you have found your faulty switch. Never seen anything else cause that issue.
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I had the exact same problem a couple weeks ago with my Johnson 150 and posted on a boating forum. I figured it was probably in the remote switch rather than the one on the motor. Another owner had same problem after a rainstorm and since my problem began after driving back in heavy rain, it appears to be rain that got into the remote switch. I just let mine dry out and it hasn’t done it since. Did yours get wet too? You could try spraying lube in the switch or a blow dryer if it doesn’t dry out on its own. If you find out something else let us know in case mine happens again.
18.5 Baycraft Flats Edition
Johnson 150 Oceanrunner
Wood Driftboat
good ideas
we have also seen issues with the wire going to the remote switch. it will rub where it loops around inside the shifter, and it can short out against the shifter.
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I had that problem, but it was with my jackplate. It was a problem with the wire to the switch.
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Thanks, I will check out the switch on the side of the motor and if that doesn’t work I will the check the one on the throttle.
Gene
Had the same issue on the starboard engine. Unplugged it, took it out and found saltwater corrosion inside. Replaced switch, problem solved.
GW 232GT Gulfstream
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Had a boat do this while running, the wires inside throttle control had rubbed to where the insulation was worn through and the bare wires would touch. If not on the boat its probably the switch but if not check the wires.
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