Power Trim Issues: Trapped air or bad, 86 Mariner 115

[wcsd106]

I recently bought a new (to me) boat with a 1986 Mariner 115 Inline 6 cylinder outboard. The previous owner stated he had installed a new power trim motor, but that he believed there was air trapped inside it. I believe most of these systems are self-bleeding, but I know a lot of the time people do not get them filled completely. However, I've been working with it most of the afternoon and am getting no closer to a solution. I am beginning to wonder if the pump itself (not the electric motor) may have some issues. Please read what I've observed.

---

Here are the symptoms I'm seeing:

• Power Trim Motor runs and sounds strong on both UP and DOWN cycles
• As outboard is trimming up or down it will occasionally stall and the motor will seem to rev and get louder.
• Sometimes the stall will clear itself and the outboard will resume its movement. Other times you must stop the power trim motor and then start it back up.
• The outboard will trim completely up, but it is VERY slow to do so. I get more instances of the stalling on the up cycle than on the down
• At full up or full down the motor sounds like it is running dry and trying to suck in more fluid.
• After a few cycles, if I bring the outboard all the way up and open the power trim fluid fill neck I sometimes see tiny bubbles in the fluid
• After a few cycles, the trim fluid level will be lower. I refill and then begin running up/down but I never seem to get all of the air out
• I have used one complete tube of power trim fluid and part of a second but the problem is not getting any better.

---

This afternoon I was by myself so I was unable to see the trim cylinder during up/down movement to see if any fluid was leaking out of the cylinder. I will try and get a video tomorrow to better show what I'm dealing with. I have also attached two pictures of my power trim pump for identification purposes.




I'd greatly appreciate any help that can be provided. Thank You.

 

[Chris1956]

It sounds like it indeed has air in the fluid. Trim it up and let her sit 10 minutes. Now open the cap and refill it. Cycle down and back up and let her set 10 min. The air needs time to bubble out of the reservoir. Repeat i\until she runs smooth. The tilt tube is greased and not binding, right?

You may use Dextron III auto transmission oil, instead of power trim fluid. You should also see any leaks of fluid, even when working by yourself. You could jumper the solenoids (cowling off), at the motor so you can stand next to her and run the trim.

 

[Chigwalla]

Check that the manual release valve is closed. If it is, it might need new O-rings (quick & easy job).

"After a few cycles, the trim fluid level will be lower."
Where is the fluid going ?
If the reservoir really is full, it has to be coming out somewhere...

 

[wcsd106]

Chigwalla, I think there might be something to the manual relief valve. I was digging through the OEM Mercury manual for this outboard last night and studying the diagram and workings of the power trim system. When I got home this morning, I went to check the relief valve. What I discovered is troubling: It looks as if the relief valve has been replaced with your every day run of the mill hex bolt. Either that, or I'm going to be rich because I'm the only one on Earth that can get Nylon to Rust.

I attached a picture of an OEM Relief Valve for reference.

Chris, I haven't had a chance to run it up and down this morning, as I've been trying to get other necessary projects finished. However, I would like your opinion as well on the state of my manual relief valve.

Thank you both.

 

[wcsd106]

I've attached a video of the power trim in motion..

Here are a few things to note that are not seen in the video.

• After raising the outboard this time, the reservoir was again a bit low. I topped it back off.
• Before raising and lowering the outboard, I put a piece of cardboard under the transom and engine to catch and show any dripped fluid.
• No fluid leaks were observed. I will be leaving the cardboard in place overnight to see if any drips appear as it tries to bleed down
• The outboard went down much more smoothly than it has.

I'm certain the jury-rigged manual release valve has a little to do with the air, but I'm betting there was/is a TON of air trapped in this system. Please take a look at the video below:

 

[Chigwalla]

Is that for real or are you having fun with us ?
That's some sweet backyard hackery right there, my friend.
Wanna bet whether or not it's JB Welded ?
If it's installed just to plug the hole, that's the problem since most of the pressure is going through the bypass right now.

Looks like it's 'stalling out' right when the pump has to feed the bypass, the tilt cylinder AND the trim cylinders.
Get the bypass closed and it should be back to normal.

Good luck. Maybe start sourcing out a replacement unit just in case.
Not sure what the threads in the aluminum casting are going to look like when that bolt comes out...

 

[wcsd106]

Is that for real or are you having fun with us ?
That's some sweet backyard hackery right there, my friend.
Wanna bet whether or not it's JB Welded ?
If it's installed just to plug the hole, that's the problem since most of the pressure is going through the bypass right now.

Looks like it's 'stalling out' right when the pump has to feed the bypass, the tilt cylinder AND the trim cylinders.
Get the bypass closed and it should be back to normal.

Good luck. Maybe start sourcing out a replacement unit just in case.
Not sure what the threads in the aluminum casting are going to look like when that bolt comes out...

I wish I was joking about the bolt. Unfortunately I'm not. I have ordered a replacement manual release valve... genuine mercury. It should probably arrive later this week.

In the event that the threads on the casing are screwed up, I have located a suitable replacement at a parts yard here locally. It's going to cost around 200 if I have to get it, which is about the same as one would be from eBay where I don't know the seller.

Once I get a free moment today I am going to remove that bolt for a visual inspection. I figure at this point it really can't hurt anything.

 

[wcsd106]

Update 7.17.17:

I removed the bolt, washer, and whatever nylon washer that had begun to disintegrate behind the metal washer this afternoon. I'm keeping my fingers crossed that the threads aren't too screwed up. I didn't see any signs of thread damage aside from some chipping of the aluminum on the outside of the casing. I stuck a tiny screwdriver back into the hole very carefully to feel for debris or leftover pieces of the original release valve.. It appeared to be clear and empty.

It would appear, from a quick glance, that whoever did this stuff just wrapped a bolt they had lying around in a ton of teflon tape until it would thread into the hole. If so, that may be my saving grace.

The new valve is on the way and should probably be here in a few days.

Anyway, I thought you guys might want to see this piece of shadetree engineering:

 

[Chigwalla]

Good heavens.
Thanks for posting that.
I realize not everyone's "mechanically inclined" but I am blown away that someone thought that OK to do.
Lucky break on the internal threads. Was there any water in the oil ?

 

[wcsd106]

Good heavens.
Thanks for posting that.
I realize not everyone's "mechanically inclined" but I am blown away that someone thought that OK to do.
Lucky break on the internal threads. Was there any water in the oil ?

There didn't appear to be any water in the oil. I suppose that makes me twice lucky on this. I hope it can hold out.

 

[jimmbo]

Inbred engineering at work

 

[wcsd106]

You're not kidding, Jimmbo. What's even worse is I'm sure the previous owner paid good money to whoever did this crap.

 

[wcsd106]

:mad-new: :mad2: :frusty:

I Believe My Luck Has Run Out


Well, I received my replacement release valve this afternoon and had to force myself to mow the lawn and get some other chores done before messing with it. I believe at this point my luck has run out. The new valve will not go in all the way because there are still bits of plastic from the original release valve hung up in the threads of the power trim unit.

I've spent the past hour or so digging at them and bringing them out piece by piece. The only good side to this is the pieces coming out are only plastic. I have yet to see any bits of aluminum come out with them.

I do believe, however, I am fighting a losing battle, since there may very well be more of that valve further down where I cannot get to it.

I have already checked and the outboard graveyard about an hour or so north of me has two of these units (One Gray, One Black) that are both needing the pump (Which I have) I am going to call in the morning and verify they still have at least one available and then I guess I'm making a trip to get one.

Once I get the old unit out (Correctly as per the OEM Manual) would there be any way to try and get the remaining bits of plastic out of the threads? I'm working in fairly close quarters right now with the unit still on the boat. I have cracked my head on the midsection of the outboard at least a half dozen times tonight... Which, incidentally, is making me want to find the idiot who did this even more.

Guys, thank you for all the help you've been giving me. I hope you all will stick around to see this to a working resolution.

 

[Chris1956]

Gee, it is not that much work to take the unit off the motor. You will probably need to remove one of the transom brackets to get it off. if you can get all of the broken relief valve out of her, maybe all you will need is the new valve.

 

[wcsd106]

Gee, it is not that much work to take the unit off the motor. You will probably need to remove one of the transom brackets to get it off. if you can get all of the broken relief valve out of her, maybe all you will need is the new valve.

I was able to get the remaining bits of plastic out last night and get the new valve inserted. After filling the system, i saw marked improvement, but it was still having difficulty going up all the way. Once the two outside rams were maxed out and the center ram took over, it would fall on its face.

Changing the system out is fairly easy. You do have to remove the starboard bracket, but that's the worst part of the whole thing.

I made a trip to the graveyard today and picked up a power trim system complete except for the motor. Going to try and change it tomorrow if I have time.

The place I buy salvage parts gives me 45 days to check it out in case something happens. He had about a dozen of these systems on hand.

 

[Chigwalla]

Might not be posting too often but I want to see how you make out. After what you found, it's definitely not worth pursuing unless you're going to tear it right down to clean it out. Even then, there's not a lot of availability of internal parts.

You're gonna need to pick up a new trilobe pin for it too.

 

[wcsd106]

Hey guys I wanted to get back with you and let you know what I've come up with. On Thursday I made a trip to Beecher City Illinois and picked up a replacement power trim manifold and Rams. The only thing it needed was the pump and motor which I have a brand new one of. I wasn't able to mess with it until today due to working overtime, but this morning I went out and got the old power trim removed and then installed the new one. Installation went without a hitch mostly due to the fact that I have the OEM Mercury repair manual for this outboard. After installing the new power trim and doing the initial Reservoir fill, I began cycling the motor to raise and lower the outboard. Each cycle resulted in a very pronounced puff of air when I removed the fill cap. The system bled easily and moves up and down without any issues.

The only other issue I ran into is the relay system that controls the power trim motor. It is wired less than ideally, but I have the proper wiring diagram and will be redoing the connections in the next few days.

I will make it a point to post another video once my work is completed on the outboard.

I want to personally thank everyone who assisted me in this thread. I honestly believe I would still be standing there scratching my head had it not been for your wisdom and knowledge. Have a great day and I will follow up on this thread later this week.

 

[Chigwalla]

Looking forward to seeing the next installment.
Rock on !

 

[wcsd106]

Working great & I even added a nice new feature to help me out. Thanks again for all the help!

 

[Chris1956]

Sounds good.....best of luck