tcelano

This may be implied in some of the other responses, but you could have run out of fluid in the trim pump sump when trimmed all the way up on the trailer, due to the fact that the "up" side of the piston requires more fluid than the "down" side due to the piston tailrod. When you trim back in, you then force a bunch of air into the "down" side of the rams, and the fluid comes back from the "up" side to replenish the reservoir. That is allowing you to pull up on the drive slightly, but it should still hold load down. If it squishes down when you put your weight on the drive, then you've got either a ram problem or a pump problem. Your video suggests air to me. An internal leak would result in a lot slower movement, with no tendency to return to original position.

If there are no other problems (i.e. ram internal leak or system leak), then fill the trim pump reservoir to the top, and cycle the trim rams a few times, checking your trim pump sump level.

P.S. I just got done chasing some wierd problems in my port side SSM trim system. These systems are easy to diagnose and fix when there is only one thing wrong. When you have more than one problem at the same time, it can get really confusing.

If the above doesn't fix it, post again with any new information, and we can help you work through some more tests to see what's up.

hawaiianhopper

Got to play with it a little today. Disconnected the tie rod between the drives so that I could move them independently. Cycled the port drive up and down multiple times. At the ends of the strokes, it is pretty dang solid. In the middle it isn't nearly as bad, but still not right. I think I figured it out though.

There is water in the oil/system. When I was in the engine compartment, I noticed that the reservoir was a much lighter color, almost white. I sucked what was in there out with a hand pump and then filled it back with good oil. Cycled the system a few times, and the water keeps coming back. So there is water in the system that is allowing this movement.

So what is the best method for purging the system of the water and getting fresh oil in there?

Should I:

1) Continue to fill and cycle the pumps until it's all out? I don't think that's gonna work. I'm guessing eventually the mix will become mostly oil, but will still be diluted a little.

Or...

2) Disconnect trim rams from drives. Then disconnect the last hoses in the system. Fill reservoir, and start pump and continue to fill and pump until all water is out? Kind of like how you would bleed the system I guess.

3).....?????

Thanks for the help!

JMS322

You need to find and repair the source of the water getting in to the system. My guess would be the trim cylinders need to be rebuilt.

Falcon

If you have plastic reservoirs, in most cases you can remove the reservoir that is held on with 4 phillips head screws. Then you can empty, clean, and reinstall. Fill with oil, disconnect the hoses, run in each direction until you get solid clean oil. Rebuild the cylinders, with the cylinders fully retracted, only install the trim "out" hoses, seal off the other hoses with caps or your fingers to keep them from sucking in air. Run the pump until the rams are fully extended. Attach the trim in hoses. Cycle a couple of times and you are done.

US1 Fountain

iTrader: (1)

Makes no difference if there is water and/or oil in them, neither are compressible, as far as slope. You can fill it with water and it will work fine, theoretically. But you need to find and fix the leak. Simply getting the water out and filling with oil will only last till next time the boat gets dunked, then you will be back to where you are now.

hawaiianhopper

Thanks guys. Yeah, finding the leak was obvious to fix first. I'm working on some gauges to help me with that. The service manual has a pretty good workflow to determine pressure issues.

I was looking for the specific process once that is done to get fresh fluid in the system. Sounds like you pretty much empty the whole system out and start from scratch.

I'll check to make sure all the fittings are tight. The hoses look to be in pretty good shape. Do the rams normally leak first, or the hoses?

Anyone come up with their own homebuilt gauge for diagnosing tilt and steering hydraulic systems? The Mercruiser one is almost $400. Surely it can be made for much cheaper. I have an old A/C refrigerant set of gauges that I could take and replace the gauge on. Has hoses. Just would need to get the right fittings. Though probably after making sure all the parts are rated for up to 4000psi, I'll end up rebuilding the whole thing.

hawaiianhopper

So what are yalls thoughts on fluid? Everywhere I've read and people I've talked to say that 10-w40/30 is sufficient. Heck, even the Mercury service manual says it's okay to use. Makes sense, it's just a hydraulic system.

I can go down and get the new super duper Mercury trim and steering fluid that prevents foaming, but that stuff is uber expensive.

What is yalls preference?

BTW, I think I tracked down the leak. A few of the connections were loose on the distribution block on the bottom of the drive. I'm gonna purge and refill the system and test again.

c_deezy

iTrader: (1)

The purpose of using engine oil is that it is one less fluid you have to keep handy on the boat as a spare.

seafordguy

I use 10-30.

hawaiianhopper

thanks guys!