Power Trim Issue

[bigesox11]

I have a Mercury 40 ELPTO and the trim is acting up. It will raise up but then slowly drop back when above maybe 1/2 throttle. Works fine when going slow or when motor is off. Already checked power trim fluid and it was good. Any thoughts?

 

[Barnacle_Bill]

Re: Power Trim Issue

First thing to check is your manual release valve and make sure it isn't loose.

 

[bigesox11]

Re: Power Trim Issue

I'll have to take a look. Don't know what that is, but I'm sure I can figure it out. Wouldn't that make it not stay in the up position at all?

 

[bigesox11]

Re: Power Trim Issue

Any other thoughts? Thanks.

 

[bigesox11]

Re: Power Trim Issue

Didn't see any manual release. Could I be missing something? I will have to post pictures.

 

[bigesox11]

Re: Power Trim Issue

http://i623.photobucket.com/albums/tt311/bigesox11/IMAG0197.jpg

http://i623.photobucket.com/albums/tt311/bigesox11/IMAG0196.jpg

http://i623.photobucket.com/albums/tt311/bigesox11/IMAG0200.jpg

 

[bigesox11]

Re: Power Trim Issue

To the top. I even posted pictures?

 

[bigesox11]

Re: Power Trim Issue

Anybody out there?

 

[RRitt]

Re: Power Trim Issue

sorry, just did not notice.


if it holds for days in your driveway when lifted over halfway up then the problem is in your trim spool. A new spool kit would fix it. The spool is the round little valve thingy that goes between the piston housing and the pump base. If the spool kit is not listed for your specific engine then try any other 60HP or less mariner from the early 1990's. They all used the same spool assembly.

if it eventually drifts down from any angle then the problem could be in your spool, in your check valve, in your piston, or in your release valve. Typically it costs more to figure what is broken than to fix everything. A complete ground up hydraulic rebuild only takes costs about $200 including parts. Troubleshooting a system takes about $120 in labor and you are still left needing to do the repairs. If you search ebay, amazon, google, craigslist, etc then you should be able to find a rebuild service for mercury - mariner trim systems.

 

[bigesox11]

Re: Power Trim Issue

Thanks. It will go up and down and stay there, BUT when under power it will raise up and then drop down. Weird?

 

[bigesox11]

Re: Power Trim Issue

?????????????

 

[RRitt]

Re: Power Trim Issue

Thanks. It will go up and down and stay there, BUT when under power it will raise up and then drop down. Weird?

I fix that problem all the time. It is a design flaw in the mercury system. Water enters the system when the piston is retracted. Over time it adds up and accumulates at the lowest point. The lowest point is your trim spool which is made from regular steel and it rusts out. A new spool kit will run you about $80 and takes about 2 hours to install. It's one of those parts that if you buy industrial bulk it only costs a few dollars. But how many people want to fix their boat 100 times? So you just have to pony up and pay the merc price. Since it is the off season, sending off for rebuild is fairly viable too. I'm not sure if a local hydraulics shop could do the spool or not. Might be worth taking it by.

 

[bigesox11]

Re: Power Trim Issue

Thanks alot. I was just trying to find out why it would work fine until and then drop when under power. I guess this will be a project for the winter.

 

[RRitt]

Re: Power Trim Issue

Thanks alot. I was just trying to find out why it would work fine until and then drop when under power. I guess this will be a project for the winter.

don't take the pump off of the manifold and don't mess with the big nylon release valve too much. then it will be really hard to get yourself into trouble. There is no meaningful documentation. Before taking apart set yourself up a clean area with a sketch pad for notes. When you split the piston from the base have the whole thing inside a trash bag. I've had them shoot oil 15-20 feet across the shop if I don't release the pressure first. Even after pressure is released the merc system loves to take a big oily dump on your workbench. GL

 

[bigesox11]

Re: Power Trim Issue

Thanks. Much appreciated.

 

[joesurf]

Re: Power Trim Issue

Thanks. Much appreciated.

Just reading this thread with interest. Had a failed day on the river and sounds like i have the same problem.

Tilt/trim works perfectly out of water or in but as soon as i load up the engine the trim collapses and the the prop pushes the engine fully down. I try to raise it and can hear the pump going but the tilt does not move

How did you go with the kit, is it a home job or back to the main dealer

I have a 1999 mercury 135

 

[joesurf]

Re: Power Trim Issue

don't take the pump off of the manifold and don't mess with the big nylon release valve too much. then it will be really hard to get yourself into trouble. There is no meaningful documentation. Before taking apart set yourself up a clean area with a sketch pad for notes. When you split the piston from the base have the whole thing inside a trash bag. I've had them shoot oil 15-20 feet across the shop if I don't release the pressure first. Even after pressure is released the merc system loves to take a big oily dump on your workbench. GL

Will this fault also cause the engine to cavatate and not pick up speed. I am pretty sure i have the same trim problem but also the boat is not picking up in a straight line. The best discription i have is similar to an auto car with the bands slipping the engine revs but does not pick up speed could i have a gear box problem as well as the trim?

 

[bigesox11]

Re: Power Trim Issue

Sorry. I just saw your posts joesurf. I just took my boat to two differend marinas last week. One saw no leaks and said that it could possible be some debris in the check valves. I believe mine has three. I was told that this could be causing the occasional problem.

The other marina that I took it to told me that it was normal for the motor to drop back down into what he called a standard trim position that was also a safety feature to make sure that the motor was not out of the water and not peeing water. He had me put some weight on the one side of the motor as did he to distribute the weight evenly and sure enough the motor raised up to a certain point and then released and dropped down a bit. He told me that higher trim levels were only for trailering the boat and for storage, not for when under power. The motor "releasing" at a certain point did not sound correct to me.

I talked to yet another marina on the phone and I was told that this was untrue and that the motor should not drop back down and that I should be able trim the motor as high as I want. He suggested that it may be the check valves as did the first marina I took my boat to. He said it wouldn't hurt to drain the power trim and refill so I guess I'm going to start there. I hope this helps.

I am also in the process of changing from a 13 pitch prop to an 11 to get one plane or get on plane faster when I have a second person on the boat. I am going to get it on the water as soon as I can and see if the problem continues or not.

 

[bigesox11]

Re: Power Trim Issue

Just spoke to Mercury and they said it is a safety feature. The motor will drop down to a standard or safety position when under power. The motor can only be trimmed so high before it will release and drop to lower position.

 

[RRitt]

Re: Power Trim Issue

This problem is common in mercury engines. It is a design flaw that makes the life span about 15 years with average use.

Everytime the engine is lowered droplets of water can hitch a ride on the piston shaft and get inside your system. This happens with every system. The design flaw is that Mercury did not accomodate this natural occurence. Water sinks in oil and the lowest point in your mercury trim system is the steel control valves. A better design would have had a cavity or loop to serve as a water trap. For example when you look at the evinrude trims many of them have a loop of tubing that extends beneath the tilt ram.

With normal use, the mercury trim spool rusts out and needs service after about 15 years. The symptom is that the engine will no longer hold tilt and sinks back down to trim. In the early stages of malfunction, it will hold tilt but barely. If you push down gently the engine will drop about 2/3 of the way. A good system will hold strong. Your trim ram should be rebuilt with a new top seal (where the water gets in) whenever the trim limit spool is serviced. In extreme cases, the top seal cracks and enough water gets inside to system to actually split the ram during a hard winter freeze.

The manual release rarely malfunctions on its own accord. It is just a static plug. If you did not touch the manual release then the problem is not likely to be there.

The mercury trim motors from 1993 on are all very good designs and tend to last 5-7 years longer than the hydraulics.