Mercury A-65640A control box disassembly question

Seadiver5

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Jun 23, 2017
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Hello. I've searched this forum and can't find the answers i'm looking for so I'm hoping someone will be able to help me out.

The control box on my 79 ranger bass boat has trim/tilt, electric choke, Trailer button and for some reason the engine lowering function has become intermittent. I believe the issue resides in the control box. I've been able to remove the handle and test the switch which works fine. The trailer lift button works consistently. I know how to get the black plastic cover off the control box but I'm not sure how to actually separate the alum inum box itself. It appears that I need to open that box to get to the screws that mount the box to the boat. There are two studs with nuts that I can loosen but the box doesn't separate when I do and I don't want to pry out of fear that I will break something. Is there anyone out there who knows how to take this beast apart?
 

GA_Boater

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May 24, 2011
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Welcome aboard.

Why do you think it's the remote control trim switch? Have you put a meter on the down wire out of the remote when it fails?

I would look at the down relay before tearing the remote apart - Swap relays. Relays fail more often than the switches because of the high current through the relays.
 

Seadiver5

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Jun 23, 2017
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I can't find any relays, I think it's too old for them. It does have two solenoids however...
 

GA_Boater

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Solenoids are relays by a different name. I meant to edit to say relays/solenoid - But I forgot to go back.

Same comment - Solenoids fail more often than switches because of the high current through the solenoids.
 

Seadiver5

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Jun 23, 2017
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Tested the solenoids and they both work properly, Jumpered the wires at the control box and the trim/tilt works fine. I think it's either a broken wire or corrosion in the box or switch that is the issue.
 

Seadiver5

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Oh and I still need to know how to take this box apart if anyone knows for sure how to do it.
 
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