1995 force 120 trim will go up but not down

Laser335

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Aug 23, 2016
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Hello,

I am currently having an issue with my tilt on my 1995 force 120, I have checked relays, fluid and all other troubleshooting that I could find and still nothing.

The problem: about a week ago I had my boat and everything worked as it should all day but when I got back to the dock at the launch the motor had trouble going up. The next day I flushed the system and refilled with Ptt oil and it seemed too thin once it was in the water because it would not trim while under load. After some reading I flushed the system again and used 30w non detergent oil. This seemed to work a lot better in the drive way. That next day (today) I went to check if it was still working correctly and the motor would go up but not down. The trim motor was engaging both directions so I know it was not electrical. I had to manually release it to get it down. It seems that it is a hydraulic issue, my next step is going to be to rebuild the cylinder and get in and clean the system out.

Does anyone have any suggestions? I am kind of stumped because of how good it was working yesterday.

Thanks!
 

pnwboat

Rear Admiral
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Oct 8, 2007
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I would help if you could include a photo of your system. There were several different Tilt/Trim systems used. Need to know which one you have to answer your question.
 

jerryjerry05

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No pics until he has 5 posts.
But you can post a link to a picture sharing site.

​I think his unit is the Mercury system.

I just repaired one of these.
The electric motor was full of oil and water.
Amazing thing was it actually worked(a little)
These pumps don't usually go bad but the electric motor can go out.
The seal between the pump and the shaft allows oil up into the electric motor.

Unfortunately the motor needs to come off to get the screws on the back of the pump.

Don't remount the motor until the units been filled and cycled a BUNCH.
 

pnwboat

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I would imagine that one of the valve assy. that control the fluid direction is not working. Looks like there are quite a few replacement part available for that unit, but I myself don't have any experience with that particular unit.
 

Laser335

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I would imagine that one of the valve assy. that control the fluid direction is not working. Looks like there are quite a few replacement part available for that unit, but I myself don't have any experience with that particular unit.


That's is what I was thinking, I will find out when I take it apart and clean everything.
 

pnwboat

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Here's a link to a Mercury style tilt/trim breakdown. Scroll down to the bottom. There are two types with the single ram. One with a Black filler plug, and one with a Yellow filler plug. I don't know if this is helpful, but here they are.

I've seen quite a few posts regarding the tip of manual release valve breaking off, but I don't think it prevented the motor from coming down.

http://www.crowleymarine.com/mercury-outboard/360.cfm?mdl=KXHEDF
 

Laser335

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Aug 23, 2016
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Here's a link to a Mercury style tilt/trim breakdown. Scroll down to the bottom. There are two types with the single ram. One with a Black filler plug, and one with a Yellow filler plug. I don't know if this is helpful, but here they are.

I've seen quite a few posts regarding the tip of manual release valve breaking off, but I don't think it prevented the motor from coming down.

http://www.crowleymarine.com/mercury-outboard/360.cfm?mdl=KXHEDF


Thank you for this link, I definitely have the black plug model with the square pump.

The manual release valve is not broken off, I pulled it all the way out to check for that last night after reading that it could be an issue.
 

Laser335

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Update: I think I found the issue, I drained the system down last night and pilled it off of the boat. Once I had it off it was extremely hard to move the hydraulic cylinder even though the system was not pressurized. I haven't torn it down yet but I suspect that I will find some worn out o rings.

This should move pretty freely when not under pressure right?
 

pnwboat

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Normally, yes it should move without much effort. If the cylinder is still attached to the manifold, and there is a problem in the manifold, it may not move as expected. If you haven't already done so, remove the cylinder from the manifold and check to see if the cylinder itself has any type of check valves. If you can, remove them and see if the piston moves freely.

If you already have the cylinder detached from the manifold and no internal check vales and it's still very stiff, then yes I would think that there may be a problem with the cylinder itself.
 

Laser335

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Aug 23, 2016
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Normally, yes it should move without much effort. If the cylinder is still attached to the manifold, and there is a problem in the manifold, it may not move as expected. If you haven't already done so, remove the cylinder from the manifold and check to see if the cylinder itself has any type of check valves. If you can, remove them and see if the piston moves freely.

If you already have the cylinder detached from the manifold and no internal check vales and it's still very stiff, then yes I would think that there may be a problem with the cylinder itself.

Thank you

Good idea, I haven't pulled it apart yet. I'll try this tonight.
 

jerryjerry05

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99% of boat owners DON'T lube the trim/tilt ram.
​98% don't lube anything!!
The seal dries out and seizes on the ram.
I use spray white lithium on the ram and 30wt. or WD on my steering.

Regular grease just gums up real fast on the steering and eventually it seizes and needs repair.
 

Laser335

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I agree, this is a common place to be neglected. I will post results once I track down all o rings and rebuild.

Another issue that I found is that the hydraulic shaft is slightly bent and binding... I am going to try and get a hydraulic shop to bend it back or find a used one, they are over $300 new.
 

pnwboat

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A bent shaft can cause a problem with the shaft seals and possibly the top end cap that it passes through....depending on how bent it is.
 

Laser335

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Yeah I'm thinking that this is the root cause for all of the issues that I have been having.
 

jerryjerry05

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The "bending" is usually from the steering bracket or tilt tube not getting grease or an impact like backing into something
while the ​motor is tilted up.
 

Laser335

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When I took the assembly off of the boat I noticed a bolt was broken, looks like this caused the ram to bend. The boat is out for the rest of the season now. Need to save for a new cylinder or whole new trim assembly parts are not cheap or easy to find used for this motor. I couldn't get a hydraulic shop to bend it back and they wanted the same amount to build a new rod as a new one costs. Around $350
 

jerryjerry05

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Keep an eye on e-bay and search Craigslist in different states.
There are LOTS of parts out there??
 

Laser335

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I was able to find a cheap used unit on eBay! Thank you everyone for your help.

One more question: what is the best oil to use in these units? I've heard 30w, atf, hydraulic fluid. Any suggestions?
 

Jiggz

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Non-detergent 30W oil. Although you cannot go wrong with Quicksilver's T&T oil.
 
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