Power trim won't go up all the way

I have an old '72 50hp Merc that runs like a charm, my issue is with the power trim. I lowers fine but it will only raise up 1/4 of the way and then stops...no clicking, it just stops. I assume it's a mechanical issue that's stopping it from raising all of the way. Any ideas? Perhaps someone has a diagram (non electrical) of how the trim raises/lowers?

Any help would be most appreciated.

Re: Power trim won't go up all the way

Has it always done this? Some of the trim systems have a trim limit switch that only allows it to trim up to a certain point, then the tilt takes it from there. The trim limit is to prevent the engine from being trimmed up too far while underway.

Others will chime in with more information than I have.

Craig

Re: Power trim won't go up all the way

There is a limiter on the up trim. Sounds like the up limiter is defective or out of adjustment. I don't know what side it is on (I think Port side) but the ones I am familiar with, there is a setscrew on a round disk you loosen and rotate to increase or decrease the height setting. Mark where its current setting and then play with it to see if it will go up more. If not it is defective and needs replaced. Hope this helps.

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Re: Power trim won't go up all the way

BB, if you push both top and middle buttons at the same time, does it go all the way up? If so, the trim limit switch is preventing it from tilting up, just as it should. If not, you have wiring problems.

Re: Power trim won't go up all the way

Having same problems with a Thundercraft Citation, 1982 I/O 140 Hp, not hydrallic. Old trim went all the way up. New one goes half way. On occasion, will go all the way up. I can't put into water this way, for fear, it won't go up, when I need to pull it out of the water.
Any help? Some one thought the battery, but, it was recently charged and checked out, okay.
Thanks for any help. Mike

Re: Power trim won't go up all the way

The trim limit switch is in the starboard ram bracket on these models...it is a plunger on the inside of the ram bracket and the little metal plate on the ram is what activates/deactivates the upward travel...this trim switch is wired via the blue and the purple wires that are in the trim contoller harness back at the pump end...the blue and the purple wires are connected to the trim limit switch wire via "bullet connectors"...you can make a "jumper wire" and disconnect the trim limit switch and put the jumper between the blue and purple wire in the trim harness that comes from the controller...this will tell you if it is a bad limit switch...the switch is there to make sure you do not trim the motor up out of the transom bracket side rails...the switch should be set to cut-out and stop upward travel with the engine about 1/2 inch inside the transom guide rails...the switch is set by adjusting the little metal sleeve on the ram...