1978 johnson tilt/trim goes up but not down, manual valve does nothing..

[Riptiderandy]

Hi everyone! I have read and used this awesome forum but now I'm a member My problem is that I just got my boat which sat for a few years. Got it running great and replaced a bad tilt motor. Upon testing it wont go down, if I drain it at the line itself and refill it will but only if I move it a inch or so. If I run it all the way up it locks there.....Any help would be greatly appreciated:facepalm:

 

[fireman57]

Re: 1978 johnson tilt/trim goes up but not down, manual valve does nothing..

welcome to iboats. If I remember correctly you have a blue wire and a green wire that to a relay box. Green is for down and blue is for up. make sure your relay is good on the green wire. You can also unhook it from the relay box and go directly to the battery. If it goes down then your relay is probably bad.

 

[MikeB0307]

Re: 1978 johnson tilt/trim goes up but not down, manual valve does nothing..

Is it on both switches? (Helm and cowl?) Are you getting voltage to the green wire?(down circuit) Test it with meter or test light at relay while switch is activated, if no power trace back to the switch, if power there test it at the motor, no power there, trace it back to relay, may be relay. If electrical checks out then can be caused by hydraulic issues such as trim check valve. A service manual would help you diagnose. You might wanna download it...

 

[Riptiderandy]

Re: 1978 johnson tilt/trim goes up but not down, manual valve does nothing..

Ah.. thanks for responding, it is a hydraulic issue for sure. when I try to lower it tries, just a little. The rpms dont really change so I think it may be a valve. Should I remove the manual valve and check/clean it. maybe a little junk in it or bad o-ring? Thanks again for input

 

[MikeB0307]

Re: 1978 johnson tilt/trim goes up but not down, manual valve does nothing..

Ok, if you loosened the manual release valve(accessed through hole on starboard eng. bracket) then you should be able to raise/lower the engine manually. Do not loosen it more than 1 1/2 turns though. If you cannot move it down there are 4 things the factory manual claims can cause it. The filter valve, the manual release valve, trim down relief valve, or pump control piston. If it's locked in the up position it is probably the expansion relief valve. That's according to the OMC T/T trouble shooting chart...

 

[Riptiderandy]

Re: 1978 johnson tilt/trim goes up but not down, manual valve does nothing..

Very cool, I removed the manual valve once cleaned and new o-ring. Filled and gave it another shot, still stuck. Tried to remove the valve again and it wont come out. Should I take the whole thing back out and check the other end of that valve? I'm looking for the expansion valve location now. Airlock? How do I make sure thats not it? Thanks in advance

 

[MikeB0307]

Re: 1978 johnson tilt/trim goes up but not down, manual valve does nothing..

The expansion valve is in the port side cylinder. When you remove the three screws that hold the top on and remove the top of the cylinder it is the valve closest to the transom. According to the factory manual, if the engine is stuck in the up position, that valve is your most likely cause.

 

[MikeB0307]

Re: 1978 johnson tilt/trim goes up but not down, manual valve does nothing..

Make sure you are filling it with the engine all the way up as well. If not that may cause troubles as well...