2 years ago I bought an old Bayliner bass boat. Model 1710. It's a 16 footer with an 85 horse Force engine. Both the engine and hull are a 1984 model year. It originally had power tilt but it had no power trim so I did some research and found that the pump and electric motor are the same as used for the power trim. All I needed to do was find a power trim ram which I did at a boat shop not too far away. It was actually the entire unit with a bad electric motor. I removed the trim cylinder and put everything together from the 2 units. It all works fine except that it bleeds down slowly. Most of the time I can tilt the engine all the way up and and it takes an hour or more (sometimes much more) to bleed down to where it meets the trim cylinder. Also, when I put the engine in reverse, the hydraulic system doesn't hold it down and the engine rises out of the water although when on the trailer, I can't raise the engine by hand. In other words, it seems to lock up enough that I couldn't raise the engine manually unless I loosened up the fittings to let the fluid leak out.

When I'm on the water, the trim cylinder will eventually bleed down as well. I have a spare pump so I was wondering if I could rebuild the old pump and install it. There is one difference between the 2 pumps. One of the middle fittings is in a different place. Would that make a difference?

My question is what do I need to do to rebuild it so it doesn't bleed down? What is the problem and why is it bleeding down and how do I fix it?  I'm assuming it's just an old or worn O-ring or some kind of check valve. Where would I get parts for a rebuild on one of the pumps I have and is it relatively easy to rebuild with simple tools????

An old salty mechanic at a questionable boat shop in a small town told me that the O-rings could be bought at the local hardware store but I'm guessing it just won't be that easy.

Any help would be appreciated.

I think we've talked about your tnt before, right? We have the same engine and pump/motor for tnt. If you got the replacement pump (853515A1) and not the original (F694541-2), then you should have the one that has the easy o-ring replacement. If you have the original older model, you might consider sending it in for a rebuild.

Mine leaks down as well. I talked to John at Jones Trolling Motor about it since he sells replacement pumps, and he told me his does the same thing as well and has been for the last 6 years. His advice: "Live with it". I am probably putting it on next year's to-do list, but for now it is not an issue.

I am not familiar with what is involved in the rebuild, but the information I have I got from iBoats.com. They talk about this leak down issue frequently, and have a section on the forum specifically for Force motors.

Good luck.