Tilt/Trim problem

Rudles

Seaman
Joined
May 8, 2009
Messages
51
Relays.jpgI have searched high and low and I am unable to find a sub-topic of tilt/trim. I found a few actual posts but none answered my question.

Now looking for location of the ground for the power trim/tilt motor.

My 1990 75 Merc tilt/trim isn't working. I can hear the relay when I hit the switch but nothing happens. I was told to short across the relay with the blue wire to raise or the the relay with the green wire to lower. I was told this SHOULD cause it to either raise (Blue .... raise/toward sky) or lower (Green .... toward the water) or that it will spark. If it sparked then it would indicate a problem with the tilt/trim motor. I tried shorting across both with no result period. I tried with the key on, key on and holding the switch on, key off. Nothing produced a result. Yet with the key on and hitting the up/down switch I can hear the relay.
 

RRitt

Captain
Joined
Mar 30, 2006
Messages
3,319
Re: Tilt/Trim problem

is the picture posted your actual system? if so then check to make sure motor has good ground.
 

Rudles

Seaman
Joined
May 8, 2009
Messages
51
Re: Tilt/Trim problem

It is the actual system. Where would I find the ground connection for the motor?
 

Rudles

Seaman
Joined
May 8, 2009
Messages
51
Re: Tilt/Trim problem

Hmmm, fun fun fun. Have to follow the wiring harness I guess. I am unable to tilt the engine. I tried opening the manual release. No luck. the plug is seized.
 

RRitt

Captain
Joined
Mar 30, 2006
Messages
3,319
Re: Tilt/Trim problem

Hmmm, fun fun fun. Have to follow the wiring harness I guess. I am unable to tilt the engine. I tried opening the manual release. No luck. the plug is seized.


the manual release gets "stuck" when the system is under high internal pressure. You need to lower the system down against blocks just enough to release pressure but not so much as to build up high pressure in the reverse direction. Pressure from gravity is perfect. Forcing the release open is usually a bad idea because if the nylon release splits inside system then you are pretty much FUBAR. Within my knowledge there is no way to repair a split release valve with 100% confidence other than a full hydraulic rebuild including a complete pump breakdown.

the blue and green wires in photo are only about 6" long. they go into a large black cable jacket. there should also be a black wire in that jacket. that is your common ground for trim. It MUST have a solid ground for trim motor to work properly.
 

Rudles

Seaman
Joined
May 8, 2009
Messages
51
Re: Tilt/Trim problem

Thank you RRitt. I will try to find the ground, disconnect it, clean it up and see if that helps. I would suspect worse though. It has been sitting for years. Thankfully I can get away without tilting due to having a jet unit on it so I have no ground clearance issues when trailering. I'm hoping to afford a lower unit for it next year though. That 75 on a 16' alumium scow should move along at a fair clip!
 
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