Power Trim & Tilt Leaks Down

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earl60446

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I have a 1988 48 hp johnson with PT&T, the PTT leaks down after I raise it off it's lowest position. It does not leak oil externally, never see a drop leaked but I can raise it all the way up and after maybe 30 minutes it has leaked all the way down. Whether it is on trim or tilt position, it will leak down. I am ignorant of hydraulics, hoping one of you guys can tell me the likely problem.
Meaning is it likely one of the cylinders or the motor? Could it be that air is in the system? It is an old style system, 2 cylinders and the motor is mounted outside the outboard.

I include a picture of the type it is, this is not mine, my boat is still in storage yet.

Tim
 

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Internal leak. Valve? Manual release valve is the first and easiest to check. Tilt all the way up and open the manual release valve to let the motor return. As it's coming down close the valve securely. Don't ever over tighten it. Other checks are more complicated but they are outlined in the factory service manual. Follow the hydraulic flow diagrams with your exact symptoms in mind and you can reason out where to look next. Read the trouble shooting procedures carefully, and again too...before starting any work.

I use these systems a lot. Hydraulics are dirt/moisture sensitive. The smallest piece of crap can hang a valve partly off it's seat. A worn piston or cylinder can leak by. Any corrosion inside the system is deadly. And, to make everything easier, these systems haven't been made since 1988. Place to start is always with the manual.

Hope you find your problem.
 
That is a much earlier system than 1988 but Boat2Fast pretty much nailed how to fix it. Man Rel. Valve is always the first place to look.
Only thing to add to this is that if you know your symptoms "Leaks down" for example, then when reading the manual look at every valve that has to hold pressure while raising the engine. If I am repairing one at the dealership these days we will replace all valves that need to hold pressure under thrust or hold the engine "UP" for times sake. Since you are doing it at home and time is not your enemy you can be more selective.
 

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