Mercruiser MR-1 powertrim probelms

[ToddyPond]

Hello all,

Thanks for reading the post and helping me out in advance! I have a 85 Galaxy bowrider with a Mercruiser 2.5 L 120 hp in it that I bought for $200 with the trailer last summer. Long story short I have had to go through everything on this boat electrical since it was used in the ocean most of it's life (still well worth the extra time for the price tag).

My recent probelm: the powertrim. The outdrive is an MR-1 and the motor on the powertrim works only by crossing the solenoids. I have had to fix a lot of the jimmy-rigging the previous owner did with the wiring and now I can't get the powertrim to operate by the tilt switch. I have replaced the solenoids and traced wires and tested the switch. The position sensor on the outdrive has been disconnected and cut out of the wiring and the wires to the switch don't have any external power to them.

My questions:

Do solenoids need external power (besides the battery leads) to make them engage?

And is there any harm in operating this without the position sensor working?

Thanks for the help!

 

[Fishermark]

Re: Mercruiser MR-1 powertrim probelms

My recent probelm: the powertrim. The outdrive is an MR-1 and the motor on the powertrim works only by crossing the solenoids.

What do you mean by "crossing?" Do you mean jumping them with a screwdriver or something similar?

Do solenoids need external power (besides the battery leads) to make them engage?

They are simply big electrical switches. You have a power lead from the batter and a wire coming from the trim switch up front that energizes the solenoid. Time to do some testing to see what is happening. If memory serves, there is a troubleshooting chart in the "stickies" at the top of the page.

And is there any harm in operating this without the position sensor working?

Not a problem at all.

 

[ToddyPond]

Re: Mercruiser MR-1 powertrim probelms

Thats right, jumping them with a screwdriver. Works fine at the dock, but i'm not fast enough to run back and trim up at WOT, haha! I'll take a look in the troubleshooting section and report back.

Thanks,
Tom

 

[ToddyPond]

Re: Mercruiser MR-1 powertrim probelms

I found the problem. The someone had removed a small grounding wire between the solenoids and the power trim motor plate. The motor was still grounded, but not the solenoids. It all works well now but after running for three days on the lake this weekend I have water in the oil. So starts another project! Tearing it down tonight.