Another tilt/trim question

waflyboy

Cadet
Joined
Aug 29, 2012
Messages
24
Hello all,

Warning: I'm a complete newbie when it comes to boat repair! I recently purchased a 14' 1968 Fiberform runabout with a 1976 Mercury 500 (50hp) with power tilt/trim. When I purchased the boat, the tilt/trim didn't work, so I spent some time today investigating. I'm not sure how to interpret my findings, so I'm hoping I might find some ideas here.

Before I "messed" with it, when the trim was engaged the solenoid would make a good strong "click!", but the motor would not turn.

First I found the contacts on the pump assembly and solenoid to have quite a lot of corrosion on them. Hopeful that the matter might be resolved by simply cleaning the contacts, I detached the blue and black wires from the solenoid, sanded them clean, and tried to invoke the motor to turn by touching the contacts to a 12v battery. However, there was no result - not even a spark. I used a multimeter to test for resistance between the black and blue wires and registered around 190 ohms.

I have no idea if my resistance test is useful, or even what 190 ohms means in this context. (Any guidance on this?) I'm open to suggestions on what I should look at next! Something tells me that the motor might be the problem here, based on the fact that it didn't turn when I connected the wires directly to the battery....
 

waflyboy

Cadet
Joined
Aug 29, 2012
Messages
24
Re: Another tilt/trim question

Oops! Just realized I posted this in the wrong forum! Should be in the Mercury forum. Can mods move the thread by chance? (I told you I'm a newbie!)
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,076
Re: Another tilt/trim question

Hopefully you connected the black wire to the neg post of the battery and blue to the positive post of the battery. If that is what you did, it sounds like the PTT motor is bad. Now it could just be brushes and they might be a circuit breaker inside the motor casing. The next step is to remove the motor, clean and test the commutator and test the armature and field windings. Inspect the brushes and cistuit breaker for burning or dirt. If she cleans up and tests good, reinstall and retest.

BTW - that motor should have nearly zero resistance across the black and blue wires. Maybe some rust/dust got into the circuitbreaker or brushes?
 

waflyboy

Cadet
Joined
Aug 29, 2012
Messages
24
Re: Another tilt/trim question

Thanks Chris, that's very helpful. Yes, I connected blue to pos and black to neg. I will open the motor casing next and proceed as you've recommended, then report back with my findings!
 
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