Trim pump bad?

F

fazoff

Member
Hey guys so I'm about to drop the boat in the water and I noticed the out drive will not go up or down. It's full of fluid and The pump turns on when pressing up and down.. I tried bleeding the system by cracking the lines at the pistons but no luck.. Any suggestions?
 
Is it all the way up? It could be the check valve is stuck. crack the lines loose and see if the drive will go down. If it doesn't move, tighten the lines back up and stand on the drive while some one operates the button, if it moves, your cylinders are due for a rebuild. You can buy yourself some time by smearing grease on the trim cylinder rams(shinny part) and run the drive up and down
 
Yea the drive is stuck all the way down right now. Do you think I should crack the lines loose again and try to raise it up so I can apply some Grease on the Rams and work it up and down
 
no, if the hydraulic pump is good and can't move it you ain't got a prayer...

that pump is strong enough to lift a 5000 lb boat off the ground with those cylinders and not even strain.... It can easily trim the drive up with a big block v8 pushing the drive down at full throttle

I suspect you have a pump problem
 
what year model set up is this? down pressure is only about a third of up pressure. Either the shuttle valve in the pump is stuck in the up position or the trim cylinders are stuck. Break the lines loose and see if the drive will lower, that should release the pressure on the shuttle valve. If the drive won't lower with the lines loose, stand on the drive and see if it will move, if it doesn't move then you have cylinder problems. One other option is if you have a pre 84 unit with the reverse lock out, move the shifter to the forward position and see if it will move. BTW, when you trim your drive up all the way, momentary hit the rim switch down to release the pressure on the shuttle valve when in storage
 
Good info guys- I'll get back to you with the results. The boats a 1981 with 470 I/o with a mr type outdrive. I'm going to try to trim it up in gear next
 
that is the type that uses a reverse lock valve, it could be out of adjustment. those pumps usually don't give pressure problems, but it is getting old. Is it stuck down or up?
 
The drive is stuck all the way down. I was able to push it in about 4inchs so now it's in the down position completely. When I trim up the pump just sounds like it's spinning fast.. When I hit the trim down button it's really slow sounding. But the drive is the lowest it can go. Where is this reverse lock out?
 
up pressure is pretty high on those things, like 1700 psi(IIRC), it should raise the drive up if it has fluid. Look under the pump adn make sure its not leaking from teh manifold on the bottom of the pump, check the reverse lock out to make sure its in hte proper position. Worse comes to worse, loosen the down hoses on the cylinders and see if it will move up
 
It has plenty of fluid in it. I topped it off. What's the reverse lock out look like and what should i do with it?
 
follow the plastic line that comes out of the trim pump, it should go to the shift plate, one the pivot for the shift cable, you'll see an arrow that lines up in neutral(I think), easy way is to shift it in fwd and see if it will trim up
 
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