Revspan

Wondering if anyone has any advice on a problem I have. Today I had my boat out and noticed that the trim pump really seemed to have to work hard to lift the drive. I went about the day, and when I got home, I had my wife cycle the trim up and down while I watched the trim rams. Seems that when the rams were extending, that one of them was really lazy, and actually kind of bound up, or made other cylinder work a lot harder. I then proceded to pull the shaft out of the eye end of the cylinders to watch them operate without the drive having to move, and the starboard cylinder was definitely very slow to move in either direction. In fact, the pump would start wining, like it had reached full pressure and the cylinder still wouldn't move to the end of it's stroke.

So, I was wondering if there is any valving that could cause this, or if it is simply a cylinder that needs servicing. As far as I can see, all of the hoses under the drive look very good...no kinks of any kind. Any advice??

BTW, the boat is a 2004 Powerquest 260 with 496ho/bravo drive. I think that there is about 140 hours on the boat, and it is never kept in water, always on the trailer.
Thanks in advance.

boatfast

Have you checked the fluid level in the resivor?

Revspan

Yes, I have verified the reservoir is full. starboard cylinder still will extend fully and the pump kind of "dead heads". When you pull the cylinders in(still not connected to the drive), the starboard cylinder only goes about half way in and the pump does not dead head like it does when they cylinders are forced out. Does this make sense?

Mr Gadgets

There is valving in the pump. Also the orings in the cylinder could be leaking. I have never had the cylinders apart, but I did have the pump apart. You would need a manual to follow the flow. If something was is stuck in a check valve or a bypass valve that could cause the problem??

Dick

scottw

iTrader: (1)

I had a slow drive and come to find out it was the screen on the pump pick-up was all clogged. Cleaned resovoir out and screen and added new oil. Works fine.

Thunderstruck

You need a Bravo I manual that explains what to do. Pretty easy with the procedure. In the absence of a manual, rebuild the trim cylinders. The end caps corrode and pinch the ram slowing them down. It is fairly easy. You need the rebuild kits and the end caps.

The pump has a down relief valve, an up relief valve and a thermal relief. There is a Merc replacement for each one. Also, the porting valve can be rebuilt. However, if the pump is the problem the best thing to do is to get the whole motor/pump assembly off of the internet. Much cheaper.

Revspan

I ended up pulling the cylinder off tonight. Once I got the fluid out of it, I could not push the rod in the last 3" or so. I am going to try and find a spanner to pull the cap off and see what is inside of the cylinder. It stops hard when you move it manually, which is also the same spot the the cylinder stops when using hydraulic pressure.
Anyone out there know if there is some type of spring cushion or something preventing the rod from completely retracting? Thanks!!!

Thunderstruck

The ram doesnt retract fully into the cylinder. You need to post a picture.

Revspan

Well, the cause is now understood. Seems that the piston, which is a hard rubber piece that is in the cylinder completely fell apart. It is about 1" long and the diameter of the cylinder and came out of the cylinder in pieces. Looking online, I will need a overhaul kit that costs about $104. Thinking that it might be worth it to just buy new ones. Also a lot of debris floating around, so I will need to drain and flush the whole systems. The good news is that I know what I need to do now.

Thunderstruck

While it is apart you should replace the end caps about $70 each. And by all means rebuild both rams while you are into it. Also, make sure everything is clean and is assembled in a clean area.