Yamaha Engine stuck out of the water.

[Declan]

My 50HP yamaha will no longer lower into the water on my 1999 26x. Over the last year it sometimes failed to lower. I always managed to lower it manually with a screwdriver. It nearly always raised OK with the switch.
A few days ago I replaced the Trim MOtor (the little motor that raises and lowers the engine). Worked Ok for a few days and today coming into port the engine would not be lowered by any means.
Was a fairly cheap chinese trim motor €200 . Yamaha were asking €600 for theirs. Still I would be surprised if that is the problem after just a few days use. When the new one was installed the previous one did not contain water or show any sign of a problem and worked most of the time , indeed almost always if I pushed the button enough times.
To buy the complete hydralic lifting mechanism including pistons etc is around €3500. For that amount I could probably get a decent used Engine.
Is there any hope for a cheaper solution here?

[RobertB]

Did you troubleshoot the problem to the motor? Or did you just replace what you felt was most likely?

Recommend you first sketch out the system to identify all the components. Verify the switch and fuse both in working order. Make sure the wires are good and have good connections (continuity and resistance tests). Make sure no part of the mechanism is binding. Examine the original motor by making continuity checks across the motor windings and disassembling the gearbox to check for damage and corrosion. Try running the motor dismounted and wired directly to the motor and then with stock wiring (still dismounted). Look at the motor pivot.

[fouz]

Check the solenoid on the front of the motor. When you push the button do you hear anything? Push up and listen, then down and listen. May give you an ideal if its the switch or the box.

[Highlander]

most motors have limiting switches that r used to stop the eng. on its max up & down possitions these r usually ajustable have u checked them out that should be ur first thing to check also the trim switch could be the culprit have u tried bypassing it all together hope this hepls u out

J

[Tomfoolery]

What exactly does it do when you hit the switch? Does it do nothing, and make no sound? Or does it spin, or burp just a little, but fail to move the motor?

[Declan]

Thanks.
When I push the up switch and the down switch it makes a clicking sound and a whirling sound. Sounds like it did when it was working.
I get the same sound from the switch on the engine. The engine remains stuck in maximum up position.
No investigation was carried out and the previous trim motor was declared to be at fault and replaced.

[seahouse]

Not sure how this one works, there might be a spool or shuttle valve that is sticking in the "up" position.

Or, more likely, the motor might simply reverse the pump for up and down, and the motor shaft is not positively engaging the pump (or its impeller or other driven parts of the pump) equally in both directions, or a directional valve is sticking intermittently.

How does the hydraulic fluid look for level (really that's the first thing to check) and clarity? Any signs of leakage?

But in either case unscrewing the manual relief valve with the screwdriver should allow gravity to drop the motor - that part is a mystery. Do you have a parts manual drawing or find one online?

-B

[Declan]

Just managed to lower the engine using a screwdriver head and a ratchet . Had gotten too tight for a regular screwdriver. It works fine again. Up and down no problem. This is exactly as it was with the previous trim motor. It will work fine on dry land no matter how many times I push the buttons . Sometimes after sailing it will not lower except with the screwdriver.
I had thought that the previous one was taking in water because I only had the problem after sailing. When we opened it it was dry and the oil inside was fine. So most likely the new one is also has no water inside and the oil is fine. Perhaps something else is getting wet?

[Spector]

Did you bleed it of air when you installed it?
https://www.youtube.com/watch?v=Vr_Z5tTP72U

[Tomfoolery]

Not sure how this one works, there might be a spool or shuttle valve that is sticking in the "up" position.

That's where I was going with this. Might be piloted check valves, or piloted load control valves (where the pump forces the motor down over what amounts to a complicated relief valve, with pilot pressure to reduce the relief setting when being driven in that direction), or even a directional valve that's stuck in the 'up' position and the pump always turns in the same direction, though I think that's unnecessarily complicated. Something like that, anyway.

Could even be as simple as a reversing solenoid that's not reversing motor rotation.

The next step would be to get a schematic. Electrical and hydraulic. But just the hydraulic schematic would tell the whole story. OB manufacturers sometimes are a little cagey about them, though I don't know why. These aren't missile guidance systems, after all - more like snow plow technology.

[Tomfoolery]

Just checked the shop manual for my Honda BF50. No hydraulic schematic, as expected, but the electrical schematic shows two relays; one for up, and one for down. The motor reverses rotation, rather than using directional valves.

That doesn't mean yours works that way, though. From the symptoms, it sounds like either a directional valve (changes flow direction through a loop) that's not energizing, or is stuck, in the up direction, or there's a power relay and a direction relay, though that's a bit redundant, so . . . I don't know. Really need a schematic, any schematic, to see how it works, at least from waaaaay over here.

Correction: Found an hydraulic diagram (not a real schematic, but close enough), and there actually is a shuttle valve to pilot open a pair of check valves serving as load holding valves, which in turn hold the motor in any position and against any load. Along with various thermal and shock relief valves. Complicated little devil.

Doesn't mean yours works the same way, but I think you should try to get a service manual, or just those pages, for that OB. Or somebody who knows that system. There seems to be a lot of questions on the internet about Yamaha OB's with power tilt/trim that won't come down, so at least you're not alone.

[Declan]

Have not found a schematic diagram yet for hydralics or electrics for that F50 yamaha 50hp high trust motor.

http://www.yamaha-motor.com/assets/serv ... 96_607.pdf

When the new trim motor was installed the air was not pumped out (as explained in that helpful video, thanks for that). Would cost me €150 to have the boat lifted out of the water by a crane at the marina here. I believe if I moor it with the water ballast out and lots of weight in the front, I could do it on a calm day with the boat in the water.
As the problem only occurs after a sailing trip I had suspected sea water is getting into to something (electical or hydralic). Now I wonder if perhaps its the movement that is upsetting a loose wire or loose connection.

[seahouse]

It was that the problem happened after sailing that led me to think is was low oil level. Sometimes there are baffles in a reservoir (like in a car gas tank) that would catch the oil when the boat is heeled, and if the level were low would not let it completely flow back into the depression where the pickup is located after the boat levels. The oil pickup tube could be loose and drawing air is another, though remote, possibility. Entrapped air will often purge itself after a few up-down cycles. Note that as any entrapped air is purged, the oil level in the reservoir drops.

-B.

[Declan]

Thanks. I will purge the air out of it.

[Divecoz]

I agree and its a quick easy fix.. pull the 2 leads off the Limit switch and connect them.. Now The Motor goes up and down ..

most motors have limiting switches that r used to stop the eng. on its max up & down possitions these r usually ajustable have u checked them out that should be ur first thing to check also the trim switch could be the culprit have u tried bypassing it all together hope this hepls u out

J