Trim goes up but not down...

[Animal223]

Hello,

I was having a bit of trouble and was hoping someone might be familiar with my problem.

I have a 1991 22' Regal bowrider with 1990 model-year 5.7L Mercruiser/Alpha One Gen I. I noticed during the season that although the drive raised fine, it seemed a little sluggish going down. The motor sounded fine, but the pump made kind of a squealing sound in the down direction. When it reached the end of travel in the down direction, there was no change in sound like it used to from the pressure. As I was preparing to winterize, it decided that it would no longer go down at all, even with someone trying to push on it, and the motor was spinning away - same "squealing" type noise. I ended up removing the rams from the drive to let it down so the bellows would not stretch over the winter.

Any thoughts on what could be wrong? I'm not sure if the issue is in the pump or trim cylinders. It's definitely not the motor because that got reeplaced last year when it died.

Thanks for any help you can give!
Jared

 

[yamamarinetech40]

Re: Trim goes up but not down...

Sounds like the bleed-off in pump not working....could be clogged inside....disconnect return line and operate...should get fluid back thru line going down....

 

[Animal223]

Re: Trim goes up but not down...

OK I'll give that a try, thanks for the tip.

 

[I/O WALDO]

Re: Trim goes up but not down...

Probably stuck trim cylinder(s).Rebuild time.

 

[Animal223]

Re: Trim goes up but not down...

Thanks for the help guys.

I just got the battery back into the boat this weekend and was able to try some things, and thought additional info I learned might be helpful in troubleshooting.

Yamamarinetech, I still have yet to try your solution, will attempt today or tomorrow.

I first tried moving the cyliders with them disconnected (aft end) from the drive, so basically no load. Cylinders move in and out. However, the starboard one will not move until the port one has reached the end of its travel in either direction. Both also make a "groaning" sound, as if they don't really want to move. But they will both go from one end of travel to the other.

I have the service manual, and was going to try the shock piston leak test tonight, since it doesn't require the gauges to test. I'll report back.

In any event, if anything obvious jumps to mind, I'd appreciate the assistance!

 

[Animal223]

Re: Trim goes up but not down...

Well I did some more testing, and I still don't know where the problem lies.

Yamamarinetech, I think I did what you suggested. I tried disconnecting one hose at a time at the pump. The results were:
- "Down" hose disconnected, oil came from pump when run Down, but when pump was run Up, it was like there was no load on motor (no movement of rams, no oil from disconneted line, motor went much faster than normal (no strain).
- Same deal with "Up" hose disconnected. Oil sprayed from pump when run Up, but no luck when run Down.

Is this the expected behavior?

Also, after performing the shock piston test, it appears it passed. I extended rams by running pump Up, clipped on the trailer clips, and ran pump down to squeeze clips. After disconnecting "Up" hoses on rams, no oil flowed when pump was run down.

Thanks for any help you can provide.

 

[dcmielec]

Re: Trim goes up but not down...

Try shorting the circuit. I'd bet the bank that you either have a bad solenoid or pinched wires in the throttle housing.

 

[sarantis]

Re: Trim goes up but not down...

I had almost the same problem.The starboard side cylinder looked good,the port side looked stuck.I put the parts kit to the bad one ,then both of them didn't gert in and i stopped hearing at the pump this characteristic noise of load.I assumed that the supposed cylinder needed some treatment as well since it had the same age as the bad one and i did so changing another one kit(not big cost)(indeed some orings needed changing in both cylinders).But something told me that the problem had moved to the pump that was already cleaned up.I opened it again assuming that salt or dirt had reached the valves of the pump.I took out the hydraulic mechanism(dangerous because under it there are three springs and 4 balls and needs big attention not to loose the order.With a pressure gun i cleaned first with solvent and second with air every possible way of the oil.I also replaced the 4 small o-rings at the bottom of the pump(they are behind the plate the hoses are connected to and i found them at a usual shop with car parts).After that at least at the garden (because as i was advised at sea the cylinders need much more pressure)it works perfectly).
I would suggest the following:
Disconnect the cylinders from the sterndrive only at the back.remove the 4 hoses in front .(empty them by pushing in-out)(watch if there is similar behaviour,pulling out inhale - pushing in sprays out oil)and after that do what i did to the pump.Before disconnect the pump and after having disconnect the 4 hoses work the pump a little to clean the circuit.
As about the pressure gauge I didn't use it because in Europe it's not easy to find American size connectors,bolts,nuts,etc.

 

[Animal223]

Re: Trim goes up but not down...

Thanks for the help guys.

dcmielec - Thanks for the input, but my problem is not electrical; the pump motor operates whenever it is supposed to. It is the hydraulic functioning that is not right.

sarantis - I'll give that a try. However, I am having one problem with that. Even with the hoses disconnected, I cannot get my rams to move in or out by pushing/pulling on them (even though they do move slowly with the pump). I had always assumed there was some kind of check mechanism in them to prevent motion unless it was via the pump. If someone can set me straight on that, it would be appreciated.

 

[sarantis]

Re: Trim goes up but not down...

Then i think you have to open the cylinders.It's logical that the pump can move them a little since it applies much more pressure than you can do by hand.In order to open them you have to apply much heat to the caps because they will be very stuck by salt.Personally i broke the one cap but i used stainless clamps because the whole housing was a little exensive.Good luck!

 

[Don S]

Re: Trim goes up but not down...

If you can't move them by hand with the lines off, then it's time to rebuild or replace the cylinders.

 

[I/O WALDO]

Re: Trim goes up but not down...

("I first tried moving the cyliders with them disconnected (aft end) from the drive, so basically no load. Cylinders move in and out."??? ) I have had luck on stuck cylinders by disconnecting them at the aft pin,with the lines connected and the hydrolics workin normal,get someone to hold the down button while you stick a pry bar through the end of the stuck ram and rotate the shaft.Once it goes down,runnum up/down a few times and then,rebuild that cylinder.If knott, it WILL stick again!