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Jason, Marine Mechanic
Category: Boat
Satisfied Customers: 16209
Experience:  Degree in Marine Technology. Gas and diesel marine mechanic.
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In mid summer the “UP” control stopped working at the thottle

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In mid summer the “UP” control stopped working at the thottle control on my 1995 225 Mercury Blackmax Offshore(s#0G217157), I utilized the trailer switch to to tilt up so I could finish out the summer. Now after sitting in the back yard for a month, the UP & DOWN tilt trim has completely stopped working even using the trailer switch. The solenoids click and whine but the motor will not engage. Tried jumping the soleniods with no success of engaging the motor.
Is there a way to test this system (solenoids, censors, motor, etc.) to pin down the problem?

Hello, my name is XXXXX XXXXX I will be helping you today.

I read what you wrote. If the solenoids click and the motor runs, then it should be workings. Have you checked the trim fluid yet?

Customer: replied 3 years ago.

The motor does not run even when jumpered out

So what is whining? You said something was whining?
Customer: replied 3 years ago.

The solenoids click and have a real faint whine sometimes. Is there a way to test the tilt sensor?


The tilt sensor is just for the tilt gauge in the front of the boat, it wouldn't keep the system from working. And because the solenoids are clicking, that means everything foward of the solenoids is working, and the problem is either the solenoids or the trim motor.


This is actually fairly simple to troubleshoot. Mercury uses 2 different style trim motors, a 3 wire motor and a 2 motor. The only difference is the 3 wire has a ground on the windings, but the rest of it would be the same. So to test it, what you would do is disconnect the large blue and green wires from the trim solenoids. These are the wires that run down to the actual trim motor. If you do have that 3rd black wire, just make sure it stays grounded for the test. All you do next is touch blue to battery positive, and green to negative, and the motor should trim up. If you switch them, and put blue to negative and green to positive, it should trim down.

If it works replace both solenoids. (as you would replace them as a matched set)

If it does not work, replace the trim motor. As the trim motor has either burnt out, or more likely, the oring seals failed and it got water in it and it rusted out.


Does that make sense? If it does, then that should do it. And just let me know if the ratings box gives you any problems or if you can not see it. If it does not, or you need more detail on this, by all means feel free to ask before doing the ratings. But thats all you have to do is jump the blue and green to the battery and see what happens.

If I do not hear back from you, thanks in advance, and good luck!



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Customer: replied 3 years ago.

I do not have trim gauges ... the sensor that I'm referring to is the limiting sensor that limits the range of up and down motion.

Have a look at this picture.


The tilt sensor you are refering to is the same as #15 in this picture, correct?