86 Johnson GT150 Tilt/Trim problem

mak747

Cadet
Joined
Apr 27, 2009
Messages
11
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.
 

water world

Petty Officer 3rd Class
Joined
Dec 9, 2011
Messages
81
Re: 86 Johnson GT150 Tilt/Trim problem

there are special adaptors that omc made when engine was built to screw in various plugs in unit.
 

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: 86 Johnson GT150 Tilt/Trim problem

An OMC Factory service manual would really help you out with your probs. Good trouble shooting procedures and pics.
 

James R

Commander
Joined
Feb 1, 2007
Messages
2,679
Re: 86 Johnson GT150 Tilt/Trim problem

I have long since given up on the hydraulics on T/T units. Without the proper test rigs you are beating yourself to death and at the end of it all it turns out to be some little valve that you can't replace anyway. I find a good used unit and replace the whole thing.
Defeatist maybe but I am still sane,,,, I think.
 
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