Went out on friends boat last weekend, we dropped his boat into the water and could not lower the drives. Heard the trim pump motors running. But not lowering. Tried standing on the drives, no luck. The motors sounded like they do when you come to the end of the travel, making that higher pitched noise.

I switched the outlet and inlet hoses at the pump. hit the up switch and the drives went down. But would not come back up. So I switched them back and left the drives down

Is there a valve in there thats stuck? is it something rebuildable? Any other ideas?

BTW, Mercury Bravo 1's with the factory trim pumps, early
90's vintage

Could be the Solenoid sticking or low on fluid. Sometimes if you tap the solenoid while it is being activated it will drop into position and reverse the direction that you want to go. That is usually the culprit.

Do the solinoids reverse the motor to make it pump the other way? If so I am not sure thats it, because we could definately hear the motor turning either way you hit the switch.

My first thought was they were a little low, so we topped them off. Of course when we did get them down they overflowed out of the cap, all over the place.

sounds like the trim cylinders may need to be rebuilt, when you put the drives all the way in the up position and the cylinders bottom out all the pressure from the pump may be pushing past the inner seals and putting pressure on the down side of the seal which also jamms up the down solenoid with pressure..holding the trim switch in the down position with someone literly jumping down on the drive will sometines release the pressure, or just crack the lines but be careful because the drive will come down on you..

I tried standing on the drives and jogging the switch/motor, no luck. Tried cracking the lines and standing on the drives, no luck.

It only came down when I switched the lines at the pump.

The end caps on the cylinders will corrode causing the cylinders to bind up. The Up pressure is higher than the down pressure, also there is more piston area for Up. This is pretty common. As MrFixxall says it can also be the seals.

Mbam, How do I verify or diagnose the end caps or the seals as the problem? And if thats it will I need all new cylinders?

I have had the same problem with my trs drives and they were low on fluid. That would be the first thing I would check if I were you.

Had this problem before. Hte high pitch sound is the pump pumping dry. It goes faster since there is no fluid to push. Are your limiters messed up? Check them and maje sure your drives dont think they are always in the full up postion.

you can go to bams website and order the seal kits for the rams,if its the rams and the seals are goofed up the drives will raise real slow..