So I have been restoring a 1978 Beachliner. Merc 160....trim pump went out, Can't afford to have it fixed. Can I just remove rams, hold drive up with 3 or 4" piece of PVC and not use reverse?
Are you sure the trim pump is bad?
It could be the up/down relays.
Mine has two relays (solenoids). One for up and one for down. Those things can easily fail especially if the boat has been sitting for a while. The contacts get corroded and nothing happens when you push the button. They are very inexpensive. Under $20 if I recall.
I would try to energize the trim motor without the relay(s). Basically bypassing the relays.
On mine, the blue (like the sky) wire is up, green (like the grass) is down and the third wire is the negative.
You can easily apply temporary 12 volt positive to either the blue or green to see if the motor responds. Make sure you get good contact with shiny clean wire. Take a blue or green off the relay, clean it up nice and shiny, then apply 12 volt positive.
Report back....