"A couple things come to mind
"A couple things come to mind right away. My first guess would be poor voltage to the pump motor caused either by a bad wire, connection or relay. (I'm assuming the battery is OK) A bad motor. Or possibly a damaged hydraulic hose. This could be either damaged externally from being pinched or kinked somewhere, or internally due to delamination. A hydraulic cylinder could be damaged internally and also your outdrive could be tight from lack of lubrication or possible impact.
After checking for proper voltage at the pump motor (under load), I would remove the tilt pin and lift the drive manually to make sure it's not the problem.
It these checks don't offer up any answers, I would swap the motor with your other one. This is pretty simple and should tell you if the motor is OK before you fork out a couple hundred bucks for a new one.
The problem could as well lie in the valve body, but we won't get into that yet.
Good luck,
Rick"
