Yahama T8 Power tilt hydraulic issue

[Yamamaha]

I recently saved a poor 2003 Yamaha T8 that needed some help. One of the issues was the PT&T unit was not working when I purchased it - the prior owner had it apart and never got it working right. With the help of this forum, I got the electric PT&T motor working again. Thank you!!! But now I find I have a hydraulic issue as well. Again, the electric motor is working correctly. With the PT&T assembly off the motor, the hydraulic piston will move up and down when powered, although it is very slow even though the electric motor turns at proper speed. However, when installed on the motor, the piston will not move the motor at all, although I can feel it trying. The weight of the motor compresses the piston and it will not hold position. With the unit removed, I can put a downward force on the piston and it will compress, so it has a leak somewhere internally. There is no fluid leaking externally from the unit. There are various valves in the hydraulic unit. Any suggestions on how to troubleshoot would be most appreciated. Thanks in advance!!!

[SouthernSailor]

If you haven't yet done so, before you take the hydraulics apart, check the fluid level.

When the motor was removed from the piston, depending on how it was done it's quite possible that some hydraulic fluid leaked out.

It's easy to check, hardest part is getting the fill plug out to check it.

Hopefully you'll find the fluid level low, top it up and everything will work as it should.

Best of luck

[Dale Shatters]

If you can push the piston in by hand and it is "soft" and feels like it is pushing back a little there is air in the cylinder. With the motor up on the support cycle the hydraulics full down then full up. Check the oil tank to insure it is full at the full up position. if not fill and recycle. If this is not the fix you have an internal bypass problem.

[Dale Shatters]

I just fixed my 150

When I pulled my lower unit on my 1998 v max 150 I noticed the PT&T cylinder head was backed out slightly. To make sure there was no damage I pulled the head and rod, inspected and reassembled. This introduced a lot of air into the system which I then had to purge. I did this today so I could tell you exactly how I did it and how it worked. My system has 3 cylinders and to start with I too could push the rod in by hand. I lowered the motor and then raised it but had to assist with the pump running until the motor was full up. I then filled the reservoir. I had to repeat this 6 times with less and less assistance in the lift until the 6th time when everything worked perfectly. I then topped off the reservoir one last time and cycled the system several more times. Perfect!

Hope this is of some help.

[Yamamaha]

Thanks everyone! This is a big help. I have the PT&T off the motor and can run it, so checking the fluid level will be no problem. I assume the way to bleed the system of air is to cycle it fully, then check the level, refill, then recycle again. Is this correct?