Merc 115 trim/tilt problem

tavares

Cadet
Joined
Mar 16, 2009
Messages
15
Last boat ride, totally unexpectedly and on it's own, my 1996 Merc 115 hp trimmed/tilted to full "up" position. This mysterious ghost trimming happened 7-8 more times over the next hour or so as we limped home. This happened with no input from throttle handle switch. When it started to trim up, I could stop it by holding the "down trim" button, but the only way to get it to trim down again was to hit the down button on the outboard itself. Of course I couldn't get this to repeat when I got the boat home by tapping on both switches, and now it works fine. My initial thought was a switch sticking, but now not so sure. Any thoughts on where I should go with this? Any help would be appreciated...Thanks!!!
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,103
Re: Merc 115 trim/tilt problem

Sometimes the toggle switches get water in them. This will cause an electrical connection to be made which will trim the motor up. The cure is to disassemble the switch and clean it up, if you can.
 

bullbat

Petty Officer 2nd Class
Joined
Mar 10, 2009
Messages
152
Re: Merc 115 trim/tilt problem

i would say to take apart and clean the switches if at all posible adnd i would put some dilectric grease also to help repell the water
 

tavares

Cadet
Joined
Mar 16, 2009
Messages
15
Re: Merc 115 trim/tilt problem

Thanks for the quick responses...I figured these would be totally sealed switches and wouldn't be "cleanable". I'll get to this right away, but won't be able to test it out for a few weeks. As soon as I get back in town and get a chance to run the boat again I'll update you with the good news (or asking for more advice). Any more thoughts on this are obviously still welcome. Thanks again for the advice. Great site - I'll be snooping around quite a bit in the future.
 

mikeneal

Senior Chief Petty Officer
Joined
Jan 28, 2004
Messages
710
Re: Merc 115 trim/tilt problem

Very common for the rubber seals to fail and allow water into the switch and cause them to false. Rememeber to turn batteries off as if it sticks in the middle of the night it can harm things as it will run till battery is dead.

Thanks for the quick responses...I figured these would be totally sealed switches and wouldn't be "cleanable". I'll get to this right away, but won't be able to test it out for a few weeks. As soon as I get back in town and get a chance to run the boat again I'll update you with the good news (or asking for more advice). Any more thoughts on this are obviously still welcome. Thanks again for the advice. Great site - I'll be snooping around quite a bit in the future.
 
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