I have a 1986 Johnson GT150 model J150STLCDC which the tilt and trim quit working on. The electric motor works but the unit will will not raise or lower the motor. The problem started with the tilt no working but the trim working fine but has now progressed to where neither work. I tried filling the reservoir with fluid and cycling the unit to bleed the system but to no avail. I removed the tilt/trim unit from the motor to try and diagnose the problem. I drained the fluid from the reservoir and found it to be very milky indicating water intrusion. I removed the electric motor and found a milky sludge blocking the screen filter for the units oil pump. I cleaned the screen and removed the oil pump to flush it out. My question is can the oil pump be tested individually to see if it is defective? The manual states that ATF fluid was an acceptable alternative to the OMC power tilt/trim fluid. I tried submerging the oil pump in ATF and then turning the pump with a drill motor but see no fluid being drawn in or expelled from the pump, is this a valid test? If not is there a way to test the pump? Thanks in advance for any advice.

Replace the complete T&T unit. Once they get water intrusion, its over.

I just happen to have one......Used. $300 TYD

That's a good deal right there.