1989 90 hp power trim will not go up only down

[weragmen]

the power trim motor works fine in the down position. When in the up position the motor seam to bind down and barely turn. Sounds somewhat like an air lock. I can toggel the switch and it will slightly move up each time. What is the likely cause if the system works only in one direction? Why is it bogging down, is there a value restrickion, or malfunction. The trim motor is only 4 months old.

[200090tlry]

Are you sure it's not low on fluid?

17mm fill on res, I put atf dexron 3 in mine calls for 2 or yamaha tilt and trim. Finding dexron 2 impossible. Check the fluid level with motor in up position. Also there is manual bleed screw that allows motor to go up and down with hand power. Lots posts on subject already

[rodbolt17]

check that your maintaining voltage at the trim relay.
hydraulically no trim up then check.
up relief valve,manual release valve,tilt piston orings or the pump.
sounds like the motor is either running on a low voltage or something(a stuck valve) is stalling the ump motor.