I am very satisfied with performance and robustness of my SternPowr model 103, but hydraulics always have some issues, not leaving me without drive, but has issues and irritates me.
Steering hydraulic system is really basic and not that bad (Hynautic), the downside is that hydraulic cylinder is underwater compared to newer outdrives and long term I am thinking of replacing it with some cylinder above waterline (that option is even shown in the SterPowr manuals and I have seen here in some thread in forum that one of the members already has done it). Main gain is in the more robust cylinder which could be always easy reachable and removable without hauling out the boat (also, two hoses less in the water). Hopefully, no need to remove it for quite some time, but since Murfy never sleeps, if it is easily removable, it will probably not malfunction, if it is not, well, you know how this works...
Now, the trim system has his own character so, I am counting on your experience, opinions and hopefully solutions. Main issue is trim bleeding down (not oil bleeding, drive leg bleeding down), especially under power, it takes between 5 and 15 minutes during ride to fall from some higher trim to the most negative trim, and while moored it takes about an hour while the leg falls from upper trim or tilt down to the most negative trim. Also if in reverse, but only with higher throttle it will trim up a bit. Since the cylinders have been redone and hoses and fittings are new, I doubt that the issue is there and since there are no external oil bleeds anywhere that left me with the suspicion on oil pump. Now, pump has only 200 hours on it as the boat itself, although it is old/original pump, but has never been used before these 200 hours made in two seasons. And at the beginning of use, I did not have that issue, than the issue has aroused. To be sure if it were the cylinders or the pump, I have disconnected the pump from cylinders and used custom fittings to connect each cylinder inlet to outlet in place of pump and used the hydraulic jack to try to move the cylinder to slip if it is up to the cylinder (I did this for each cylinder separately to not be tricked if one is good and the other bad, I mean, one blocked by connecting inlet to outlet, and the other opened and then vice versa). Anyway, neither cylinder was slipping and there were no leaks anywhere. So after that test, I have focused on the pump. Sounds from the pump going up or down were normal, as expected and drive works smoothly up and down, except that I have that bleeding. So I have opened the pump and valve body and cleaned it, although it was not really dirty, but actually what I was expecting is the corrosion of checkball valves and seats in valve body, but there were none that could be seen with naked eyes, looks really neat. It took me some time to solve how to return back all those checkball valves and springs in valve body, but I have made it in the end. If anybody ever needs to do this, you can find it explained here, because I am not willing to write it here again:
https://www.boatdesign.net/threads/p...anybody.58016/
Now, although I did nothing but disassembling and reassembling and cleaning it (although it was almost not dirty), it did help and the drive stopped bleeding. But, that lasted about one month and the problem has returned. Since recently, there is also some squeeky sound from the pump when trimming down, when trimming up sound is normal.
So has anybody here encountered this problem and knows the permanent solution? Have I assembled the valve body in a wrong way, or is it really that sensitive even to a small dirt or this means that small checkball valve seats are not good anymore and that valve body should be replaced/redone? Or am I missing something?
I would like to add that I am using ATF oil, although it says in manual it should be used SAE-30. It is a mistake I have made at the beginning, somehow I remembered incorrectly that it is same oil as in steering system. After reading many sites, forums and similar, I have decided to live it that way because many people are doing it already without issues. Actually, it was a PITA to remove and clean all ATF oil from the system to pour clean SAE-30, so only reason is that. What I have found on forums is that ATF oil can destroy some seals in the system because of included detergents/additives. But, while disassembling the pump, I have not encountered any rubber seals, only seals I have on the pump is one O-ring on the oil pouring plug and one quad-ring on the vent screw. So I am confused. Or are there some rubber seals that I am missing?
I would appreciate any help or advice since a couple of you are using the same drive and have experience.
Thank you!
breezy
