Trim tilt technical questions

[taylorjm]

2007 Bentley Cruise 200 and a 90hp Mercury elpt 4s engine.

Just bought the boat. Found the engine will not go up. The electric motor runs, but won't go up. Checked the fluid, added fluid. The reservoir was full but if I ran the tilt up I could put some more in, but when I stopped running the tilt, it would gush back out. I did manage to get some more in, and now it does go up and down, but it doesn't sound the best. Checked the fluid and it's really foamy. Looks mixed with air, not water. Also noticed the seal at the top of the cylinder, where the top meets the case, not the shaft seal, there's a leak. Once the motor is up, it seems to stay up without a problem.

My questions are:

Is this a double acting cylinder? I would have though the fluid would stay at the bottom half of the cylinder and push it up, then just pump the fluid out to let it come back down. Why is there fluid at the top half of the cylinder? Unless the piston o-rings are bad.

Does it sound like it just needs the o-ring kit and to be flushed out and refilled with fluid? Has anyone seen damage to the cylinder walls that would mean more than an o-ring kit?

I have no idea on engine hours, and don't know how to check it. I did just order a seloc outboard manual, so I won't be going in blind.

From what I can tell, I need the fancy tool to take off the cylinder top piece. I would guess you want to loosen that up while it's still on the boat and have some leverage. Then remove the cylinder/motor. Remove the piston, replace the o-rings, put back together. Fill and cycle with fluid while on the bench? Then put it back together?

Thanks!

[taylorjm]

Well I've done some research, and found the cylinder is indeed a double action. So there's pressure on the bottom to make it go up, then pressure on the top when it goes down. Mine doesn't have an issue going up once it has fluid, but when it goes down, it leaks around the edge of the cylinder and the cap. I got a spanner wrench and found the cover was really loose. I was able to get a full turn on it before tightening it up. I thought this would solve the problem but it didn't, so the o-ring on the cap must be bad. So I'm thinking the o-ring kit should fix things right up.