Trim NIGHTMARE for 150HP Mercury Black Max

Clayjunky

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Feb 23, 2010
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13
I need help folks,I just installed a new trim motor and now the motor goes up but does not stay up unless you manually press in this cylinder/solenoid looking thing- The cylinder appears to have a wire post to be connected to 'something' but the wiring diagram that was included in the new trim motor didn't address this, nor did the hardware included with the motor. I bought the boat without the trim connected, so I'm stumped. Anyone have a similar setup and can provide assistance? The boat is a 150hp Mercury Black Max on a 1989 Sea Ray. Thanks for your assistance-
24429d1308312793t-trim-motor-wiring-issue-trim-jpg
 

Laddies

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12,218
Re: Trim NIGHTMARE for 150HP Mercury Black Max

That's the reverse lock valve it should have a wire coming from the shift switch to activate it, it may not be hooked up right, it could be sticking from dirt or it or the shift switch could be defective.
 

Clayjunky

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Re: Trim NIGHTMARE for 150HP Mercury Black Max

That's the reverse lock valve it should have a wire coming from the shift switch to activate it, it may not be hooked up right, it could be sticking from dirt or it or the shift switch could be defective.

Thank you so much! Any idea the color of the wire or where it would be housed (engine or control box?) ANY additional info you have is very much appreciated.

Regards,

Clay
 

monk-monk

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Aug 27, 2006
Messages
642
Re: Trim NIGHTMARE for 150HP Mercury Black Max

Clayjunky, 2 things about this type of trim pump control valve...the piece you are speaking of is a Plunger Solenoid...this solenoid receives Positive battery voltage when the ignition key is turn to the On position...this solenoid controls Down cycle hydraulic pressure....it is basically a pressure relief valve, if there is TOO much Down pressure, it will "pop" out and release the Down pressure....look at it like this, if you are raising the engine there is not too much that can go wrong, but if you are trimming the engine In, this creates a "crush" zone...so the solenoid plunger will kill Down pressure if it gets enough resistance...NOW, it can affect the Up pressure cycle too...BUT the manual release mechanism (it is to the right of that solenoid plunger) it has a little "tee" handle on it...that release mechanism must be turned clock-wise very tight...if it is not real tight, THAT will let the Up pressure bleed off...problems with the manual release mechanism is most likely the problem...i use a Mercury test gauge set to rebuild these pumps, it determines if the problem is in the release mechanism, or if it is a pump cavitation problem...gotta have a test gauge set to be able to determine the true cause of the Up pressure bleed-off...
 

Clayjunky

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Re: Trim NIGHTMARE for 150HP Mercury Black Max

I can't thank you folks enough for the info you have provided. I do have another question though. The photo below indicates it is a Wiring Harness for the trim motor, yet as you see from the first pic in the thread, the pump came with new wires and didn't have this harness included. I did find this harness on the boat among some miscellaneous junk and I'm curious what the pronged end with the rubber gasket goes to, as the new trim motor didn't have this included? Inside the rubber end there are metal prongs that must attach or make contact with something, but I'm not sure what. Thank you again for taking the time to assist me- Clay

a20792a12d2e1f80c961f8_m.JPG
 

Clayjunky

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Feb 23, 2010
Messages
13
Re: Trim NIGHTMARE for 150HP Mercury Black Max

Bump.....any info on this wiring harness? Thanks
 

Laddies

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Re: Trim NIGHTMARE for 150HP Mercury Black Max

Most trim pumps of that era had a 3 wire power plug on them, that is a adapter.
 
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