possibly bad solenoid on trim tab pump.
you can try to switch them and see if opposite side start working
if not piston may need replacement

 

I used a floor jack and length of 4x4 while trying to move it up to free mine up a couple years ago.

 

I had a very similar problem and it ended up being dirty electrical contacts. You should clean the connectors at the pump and also the connections at the switches. You can also switch the lines from port to startboard to ensure the cylinder is working correctly. The solenoid will prevent you from moving the trim tab so I wouldn't try to force it even if the switch is pressed.

 

I was skeptical as well, but a marine mechanic with 20+ years experience recommended this to me after confirming that I could hear the pump running at all switch positions, the tab wasn't all the way up, and that the other tab worked. It didn't take much force at all. There was a light "pop" and it been free and working well ever since.

 

Thanks so much. I'll be at the boat all weekend so I'll give all these suggestions a try. Thanks.

 

Just a follow up...port side tab was stuck fully retracted. Just a little pull while a buddy hit the switch got it free. Ran like a top this past weekend.

 

very helpful... will try this tomw!

 

Do you have a Bennett system?

If so, when the motor runs in forward to pump fluid, the solenoid must also receive 12 volts to energize the solenoid to allow the fluid to flow into the line.

If the motor runs, either the solenoid is bad, or the connections at the switch need to be tightened or recrimped. The starboard side solenoid is typically the green wire on the bennett system (as long as the hydraulic lines aren't swapped accidentally).

Doug

 

mine moved with a little 'tug'.