Starboard side trim cylinder on Alpha I doesn't move

[Gunn]

A few weeks ago I had an issue where I could not get my port engine Alpha I sterndrive unit to go down. The motor would run, but nothing would happen. I ended up having to "help" it down. When it would go by itself it was -very- slow, then it would stop again and need some help.

I got the boat home and removed the sterndrive to clean it, paint it and replace the water pump. While it was off, I ran the trim pump. What I found was that the port side trim cylinder would move up and down. But the starboard side wouldn't move. This seems to be a clue, but...to what?!

I'm leaning towards it being the down pressure relief valve in the trim pump. In the Mercruiser service manual, there is a In/Down Pressure test section (5A-5), where if the pressure is not up to spec (400-600psi), then the first thing to change is this relief valve. Unfortunately, I don't have the hydraulic pressure testing gauge.

If anyone has had these symptoms before, I'd appreciate hearing how you ended up fixing it.

Thanks,

Tom

 

[mysticowner]

That's the first issue we had with the boat we bought last winter. The cylinders in our case were the problem. They
were frozen in place and not by the temp. It was corroded. I rebuilt the cylinders and all was well.

I chased the pressure questions as you are. What I did was unook the cylinders to see if the drive would lower on it's own.
It did. Then took off the hoses to the cylinders and they still wouldn't budge. That's the easiest way I found
to diagnose the problem.

 

[Gunn]

Great info, thanks! Surprised I never received any other responses from anyone with this issue here.

In any case, what ended up working for me was just exercising it a lot. Eventually I could just lean on it with someone else trimming it down to get it to go. Now, it is nearly normal. Only slightly slower than the starboard side outdrive.

So I have seen rebuild kits that are way expensive (>$150), and I have seen a seal kit that is relatively cheap (~$30). Not sure what is in the expensive kit, but what did you end up doing, taking it apart and replacing the seals? I will probably tackle that project during the winter.

Thanks

Tom

 

[mysticowner]

The seal kit and a major clean up took care of them. I believe the expensive kit had the ram with it. I'm not sure though.

 

[Gunn]

Great, thanks! I guess thats my first thing on the to-do list for the winter season, if it holds out that long.

Tom