Re: Tilt & Trim
it needs to be thoroughly and securely blocked and braced into the up position. You can lose fingers and stuff if the engines falls on your hand.
I have rebuilt hundreds of these systems and I have only seen the piston housing go bad for a very few reasons:
1) it freezes low enough and long enough for the water to separate out and get trapped in the vertical fluid channel that runs along outside of cylinder housing. When frozen, water can split the channel like a pipe. 90% of the time the crack is on outside and clearly visible with a puddle of oil in the snow.
2) saltwater boats with galvanic corrosion can seize the lower mounting shaft, pit the housing, or corrode the cover threads so badly that the unit will cost more in labor to repair than to replace.
3) if an object is struck in the water at high enough speeds, the bypass valve may not allow fluid to pass fast enough and the up fluid channel cracks from back pressure (identical result as freezing but from different cause).
4) frustrated and careless owners can whack the thing with a hammer and put the cylinder out of round
In general:
look at the top, center seal of your cylinder housing. If it shows any sign of hardness, cracking, or fatigue then replace the cylinder seals. As long as the top seal is keeping water out and oil in, then the ram is probably fine. One exception is a badly neglected trim motor that allows water to enter reservoir. The water gets into cylinder, rusts out the bypass valves, and hardens the orings. The motor should be replaced when it starts roaring (bearings) or vibrating. If you wait for it to die then you may end up ruining the whiole system from water intrusion.
all that said and done - if it has oil, the motor spins, and it doesn't move - then your best bet is a full hydraulic rebuild.
