87 Force 125, Tilt and trim only goes up. Suspect pump.

Solkin2k

Recruit
Joined
Jun 16, 2020
Messages
4
Good morning, I have a problem with my tilt and trim system on my 87 Bayliner, with a Force 125 hp. I have done some extensive troubleshooting already via many resources that I have already found online. I have come to the conclusion that I think that it is the pump. But before I fork out a pile of money for a new one, I thought I might be able to get another opinion.

The problem is that the motor will only trim and tilt in the up direction. Will not go down.

I took the trim/tilt motor apart first and it was extremely dirty, it even had water in it. I took brake cleaner to it and gave it a real good scrubbing as well as replacing the o-rings.

I then disconnected all the wiring from the both relays and gave them a real good cleaning, they were extremely dirty and corroded. Plugged everything back in and gave it a try.

After the cleaning, the motor sounds a lot better and a lot more powerful in both directions. But, still no downward motion in the cylinders.

This is where I decided to remove the return lines from the cylinders to the pump. I have both completely removed assuming that the engine would lower on its own, but nothing happened.

The moment I start to loosen off the fill lines, fluid started leaking out and the engine slowly lowered. Once completely lowered, I put everything back together, and filled the system with fluid, assuming there was a vacuum that was holding everything in the up position.

I hit the up switch and everything trim and tilted upward like it was brand new (after the motor cleaning I would assume). Then when I hit the down switch, the motor started running and nothing happened. The tilt was once again stuck in the up position.

So I sat thinking about it for a long while and decided to remove both return lines again, and loosen of the fill lines, and let the motor slowly tilt and trim back into the lowest position. I then re-tightened the fill lines and left the return lines off.

With the system left like this, I hit the up switch and it attempted to lift the engine up with what little fluid was left in the system. Then I hit the down switch. (This is where my attached photo comes in, there a yellow numbers by the ports in the photo). When I hit the down switch, it started pushing fluid out of the #2 port in my photo and not the #1 port. I am not entirely sure how this system works, but this doesn't seem normal to me.

Port 1 is attached to the tilt and port 2 is attached to the trim. There is no fluid being pushed out of port 1, and understanding that the tilt cylinder has to retract first and then the trim cylinder, this seems to be the problem. Making an educated guess that something in the pump has failed and I need a new one.

I am just wondering if that's what I've got going on, or maybe it is something else, before I spend the large sum of money to buy a new pump. Thank you all for your time.
 

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Solkin2k

Recruit
Joined
Jun 16, 2020
Messages
4
Update:

I pulled the valve body off the motor today and removed the valves. I found a broken O-Ring, which I then replaced with a new one. I put the entire system back together, refilled the fluid and tried it out. It works! It goes up and down great! But, it has now created a new problem. Now, it won't stay tilted up. It will slowly lower over time. It will lower all the way down, depressing the trim cylinder as well.

At first I thought that it might be the O-rings in the tilt cylinder needing replaced, but it will also depress the trim cylinder. There must be more issues with in the valve body somewhere...
 

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jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
18,113
You seem to do a lot of research??
Did you read the first 5 posts in the Force forum?
Your answer is in one of these posts.
I'd tell you but you really need to explore them.
It's an easy fix that you already held in your hand:)

These pumps either work or not.
There is nothing in the pump itself to fix so don't take it apart.
 

Solkin2k

Recruit
Joined
Jun 16, 2020
Messages
4
Haha, thanks for making me find the answer myself! :facepalm: But, in all seriousness, yes, I have read those posts that you mention already, that's how I figured out how to pull the valves out and discovered the broken O-Ring on the shuttle valve. What I didn't realize until after I had put it all back together, is that there was another small O-Ring on the inside of the relief valve. I saw the 2 on the outside and they were fine and it looked like they still worked, so I threw it all back together. I read over those posts again and learned that there was another one on the inside that can fail. So now I have to take it all apart again and inspect those. :faint2:
 

Trophy83

Seaman
Joined
Apr 29, 2020
Messages
65
Just finished this job today about 10 mins ago. Very easy you had done all the hard stuff already. Must use the panel clip pliers (Harbor freight $8.99) and the appropriate size washer to get apart. Also many good Briggs and stratton dealers will have the seals in stock. Part# 398188. Its a needle and seat set just throw the needle out.
 
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