Drives goes down then comes up?
 

the drive will go down if someone stands on it while i push the button and then it starts to come back up? would it be air in the lines if so how do I bleed them?

There might be air trapped between the main piston and the memory piston. Trim it full out and hold the trim out for a few seconds which should push some of the air out from between, then trim back in and repeat. Better?

I've never heard of it this way. Usually its the drive falling when trimmed up. In that case, it usually a valve in the pump. The system should self bleed by running it up and down several times. You can also open the lines at the rams.

Did you just do some pump work? I just remembered a situation similar to what you describe. If you hooked up the pump backwards, hi pressure "out" to the in side of the cylinder and your pump pressure is higher than the blow off memory piston reliefs (or if they leak, both sides? unlikely) it may push oil through the reliefs after the cylinder is fully retracted pushing the memory piston out. Just an extra thought.

Can't remember everything now, but back in the 1980's we had a simular problem situation when we removed the drives off a boat and then re-installed them. While we hooked everything back up we found we had gotten the hydraulic trim hoselines crossed.

I haven't done any work to the drive pumps but the previous owner might hat have because the hoses on the drive look newer that the other drive. I'll try reversing the hoses and see what happens.

Normally the black hose goes to the trim out side (LH side when looking at the pump), gray to the trim in. Then check the hoses on the outside connection block, wait, I will have to get back to you on those! I think the connections should trace transom side of block to trim out (transom end of cylinder). I will try and get a look at one tomorrow and get back if someone else doesn't pop in the answer.