77 Johnson 115 tilt & trim problem (leakdown)

[respite42]

77 115hp, model:115ETL77S, S/N J4776873. The T&T works, it will go up and down but in the up position, it leaks down in just a matter of 2-3 minutes to the full down position.
Can someone please offer info on what the problem is and how to fix it. I have just purchased the boat and haven't had it wet yet. I tried the "cycle and fill with fluid" routine but the unit was almost full already. I cycled (up and down 5 times each cycle) and checked fill about 6 times but could only add 1oz of fluid. I have ordered a manual for it. Sorry for the long post. This is my first time posting. Thanks in advance.

 

[Joe Reeves]

Re: 77 Johnson 115 tilt & trim problem (leakdown)

I know you said the unit drops down to the full down position, BUT.... does the unit actually drop that far OR does it just drop down to the extended trim rams and no further?

 

[respite42]

Re: 77 Johnson 115 tilt & trim problem (leakdown)

Vice Admiral:

Thanks for the response. Yes the unit drops all the way down to the full down position against the manual trim pin.
The tilt cylinder is on the right side and the trim cylinder is on the left side, if that helps. The ARCO # 6208 replacement motor looks like my T&T motor.
Thanks for all help!

 

[Joe Reeves]

Re: 77 Johnson 115 tilt & trim problem (leakdown)

I had assumed that you had the later style PTT assembly that rests between the transom brackets, however from your latest description it sounds like you have the add on type whereas the lift cylinders are on the outside of each of the transom brackets.

If so, at the bottom of the starboard cylinder there is what we call a "stand up valve". When this valve(#47 Part #173206) fails (cracked O ring, flawed seat, whatever), the unit will act exactly as you describe.

 

[respite42]

Re: 77 Johnson 115 tilt & trim problem (leakdown)

Thank You Joe:

According to the previous owner this is a factory unit and the motor model# indicates that it came with PT&T as original equipment. Is this valve field replaceable? I am a qualified machinist but am unfamiliar with these hydraulic units.
Thanks for the great info and the much needed help!

 

[Joe Reeves]

Re: 77 Johnson 115 tilt & trim problem (leakdown)

The valve is replaceable if you can locate one. Back then, there were two type 115hp models, one with the later type PTT and one that did not. The one that did not could be fited with the type pictured above BUT the transom brackets were such that they would not accept the later type. It could be a case that the dealership had a special running, something of that nature.