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Anybody know what to do to fix the trim on my 115 mercury? when you push hard to load the boat the trim will not hold the motor up, pushes under the boat. Not sure what I need to do? Fluid is good, checked the manual release to see if it was closed and it was.
Not real sure what you're saying ... but, have you checked the trim relays ?? It could be the relays if you can trim in one direction but not the other. If you're trimming the motor up to load the boat on the trailer and it won't stay up, then that's a different story. If that's the case, then here's something I found that may help :Quote:
Originally Posted by Countryboy N.C.
Expert: FieldServiceTech .
"First, when you service the tilt/trim unit, the motor needs to be in the full up position. That will keep the pressurized fluid from puking out the "fill" hole. To service the unit, raise the motor all the way up, use the tilt lock on your motor or a 'block' to keep it in the up position. Then remove the fill plug and add tilt/trim fluid until the fluid just starts to come out the 'fill' hole. Cycle the motor a few times in short strokes to purge air from the system. There really is no secret to servicing the unit. It's not that hard with the motor raised. I use the top of a gear lube bottle, you know the kind with the nipple tip. I cut a piece of aquarium tubing about 12 inches long and placed it over the nipple. Take the top with the hose now attached and screw it on the bottle of tilt/trim fluid. If bleeding all air from the system doesn't solve your problem, there are a couple other things that could cause your system to bleed down. There should be a manual release valve on the side of the unit (probably the starboard side). It looks like a bolt head with a slot cut through it for a straight slot screwdriver. If the seals on the release valve get worn, they will cause your problem and you will need to reseal the valve. The only other thing that could cause your symptoms are worn piston seals on the tilt rams. If this is the case, you'll have to pull the unit apart and reseal it. " (copied in part from https://www.justanswer.com/boat/25rh...old-motor.html )
Mercury Marine 115 HP DFI (3 Cylinder) (1.5L) Power Trim Components Parts
This is for a 115 3 cylinder. If you page back you can put in ser number and look at yours. If this is what you have I would say either seals on lift piston are leaking or one of the poppet valves is leaking. If you have trouble with this just post model number and serial number and we can figure out where to start you.
are you saying when you come in from fishing and loading the boat , when you drive on the trailer and gun it a little the motor drops ???? if that is the case you have the motor trimmed too high !!!Quote:
Originally Posted by Countryboy N.C.
Well I talked to a boat shop, he thought it was the seals on the piston and he is going to order me a set of seals. It is a 2003 115 ELPTO OT734019Quote:
Originally Posted by Cray
Couple of questions. Is this a problem when trimming the motor while running across the lake? Does the motor not hold a "tilt" or "trim" position when left alone?
It only goes down when under a lot of pressure , like loading on trailer, pushing it on, or running down the lake wide open it will settle some. I know something is leaking by, fluid is leaking by something, thats why it settles down.Quote:
Originally Posted by sliderman
I have one that does the same thing if I trim it up much when loading it only.but It will stay trimmed when I’m running or just setting around .don’t drop at all
If I am understanding you correctly, there is not a problem with the system. I'll give a brief description of how the system works and let you decide.
By design, from a full down position (neg. trim angle), to perhaps 15* of positive "up" angle, the hydraulics work (and hold) at a high pressure value that is needed in order to "trim" the motor while under a heavy work load. As the ram extends beyond this point, a relief valve in the system is exposed and allows the system to bleed down (at a lower pressure value) until the valve is no longer exposed. This portion of the system is referred to as the tilt function.
With that being said, if you trim the motor above the "trim" circuit while idling around and then apply throttle, the motor will over-ride the 'tilt' circuit and come to rest at the top of the "trim" circuit.
Not everyone is familiar with how the system works and it's not uncommon for owners to believe that something is wrong when it happens. As you can see, someone chimed in describing the same thing.
Only one problem, I have owned this boat 12 years, bought it new , never had this to happen till recently, its on the water 2 or more days a week all year long, my boat never sit! I have always used the motor to push the boat up that last foot or so on the trailer, I could push till it hit the stop at the front of trailer, now it goes down and pushes up on the back and makes it harder to get the boat up and the prop has hit the ramp a time or two since this started.Quote:
Originally Posted by sliderman
Got an idea about what you are saying, but if you go look at the parts list on this motor, I can't see where there is a relief valve on the piston or in the side wall. it pumps fluid in to raise the motor up, so if I have it up and then it goes down on its on, then something is leaking by, right?Quote:
Originally Posted by sliderman
There are check valves in the piston that are there for excessive pressure relief purposes. The little holes in the piston on the diagram are where they are located. They are not available for purchase separately and are not pointed out. The relief valve in the 'tilt' circuit is in the valve body. It's channeled through one of the ridges that run up along the side of cylinder. In the cylinder wall is a small hole that opens into that circuit. Once the piston rises to the point that fluid can access that circuit, you loose the ability to hold high pressure. Which means you're at the top of the 'trim' point. If you were to raise the motor beyond that point while idling around and then apply the throttle, the motor should drop to the top of the trim position. If it's dropping down below that, then yes, there is something not right with the system.Quote:
Originally Posted by Countryboy N.C.
From my experience, one of two things usually bring about trouble with the hydraulic side of the system. Either a high speed impact has caused a spike in working pressure and damaged a seal, o-ring or check valve. Or prolonged use of the system has worn the cylinder wall down and cast fine metal shavings into the system which usually leads to the check valves not seating properly.
Thanks, I see what you are saying, I'll change the o rings first, if that dont fix the problem then I'l move to the check valve.Quote:
Originally Posted by sliderman
The item between the two #2 sealing rings in the diagram is called a memory cup. If the seal on the memory cup is failing, it will cause the symptoms you described.