76 mercury 115 tilt/trim

[fishdog4449]

Hey guys, trim/tilt question here thanks in advance for reading...

Although i didn't notice it at the lake, the trim cylinders started leaking at the lake the other day and I lost quite a bit of oil. The boat had been beached for lunch and when I went to tilt the motor back down to head out, the solenoids engaged and the tilt motor spun, but the engine wouldn't tilt down. So I disconnected the lines that allow the motor to drop, and down she came but not much oil came out. When it was time to leave, she wouldn't move back up, even though the tilt motor spun. I thought that it had lost too much oil for the pump to move the engine, so rather than drop the LU to get it on the trailer I put some 2cycle oil in the trilt/trim unit just to get the motor back up for the drive home. The motor went up fine, but when I got home and hit the down switch-nothing. Not even a click from the solenoids. She wouldn't move down at all. All electrical connections were clean and tight. So I once again dsconnected the lines to let the motor come down an the oil was a whitish yellow. Drained the rest of the oil and it was the same.

Question, did I permantantly mess up the tilt motor by puttng two stroke oil instead the usual tilt fluid?
Also, why would that make the solenoids stop functioning and if it didn't then why are my solenoids not functioning?

 

[Chris1956]

Re: 76 mercury 115 tilt/trim

You probably didn't damage anything. I would refill the system with 5W-30 motor oil, since that is what was originally specified. What part of the trim cylinders was leaking? There are rebuild kits, and the standard Mercruiser Alpha I driveshaft oring is the same as the one that seals your trim cylinder rods.

BTW- Those units are not self bleeding. There is a procedure you need to follow to get all the air out of it.

 

[monk-monk]

Re: 76 mercury 115 tilt/trim

well thats a strange sequence of events! first off, "both" cylinders started leaking...thats odd that both would develope a leak at the same time! you didn't by chance over fill the pump reservoir prior to taking the boat out...this can cause blown seals in either the pump valve body or the trim cylinders? but it also sounds like you have a bad (down) solenoid. you need to check for voltage (12 volts) on the large posts of the solenoids, if you have voltage there, then you can use a jumper wire to touch between the large post and the small post where the pump wire hooks to...if it triggers the pump then its a bad solenoid. so far as hurting the pump with the two-cycle oil...i doubt you hurt it if you only ran it the little time you say you did. and the whitesh yellow stuff...when water and oil mix, it will turn to a milky whitish color, plus with the two-cycle oil viscosity it could have foamed it up from not being able to withstand the pressure. just makes me wonder how you came up with both rams leaking...and from where are they leaking, around the piston shaft itself? thats the part that actually moves in and out of the cylinder.

 

[fishdog4449]

Re: 76 mercury 115 tilt/trim

I normally use 5w30; this weekend I'm going to completely drain the unit and refill. The down solenoid may be bad, but she won't tilt up either so I'm betting its something else maybe preventing the solenoids from getting power. I'm gonna head out there with the meter and check all that out. I've had to bleed air out of the unit before, so if I can get the thing to cooperate ill do that this weekend.
I'm assuming that the piston ram seals are leaking because when the boat is in the water and occupied, a lil rainbow spreads right from the bottom of the trim cylinders. I've inspected them very very closely and I can't see any oil anywhere else on them, so thats what I'm guessing is leaking.

thanks guys!!

 

[monk-monk]

Re: 76 mercury 115 tilt/trim

hey fishdog! boy, when it rains it pours doesn't it! the solenoid thing is pretty simple to test if your mechanically inclined and have a little understanding about things. My biggest concern would be to find out what caused both Rams to start leaking at about the same time! and what is the history of this trim system, by that i mean...did it work absolutely fine for quite some time and then this just up and happened? i also believe you have sucked water into the Rams...either way, it sounds like you have a big job ahead as you will need to have the Rams rebuilt and before installing them you will need to flush the pump and lines real good before installing your rebuilt Rams! be very careful of your diagnosis and re-assembly! you first need to find the cause of the failure and then act accordingly

 

[Chris1956]

Re: 76 mercury 115 tilt/trim

Fishdog, if just the rod seal is leaking, you can replace it without any special tools and for the cost of a $3 oring. The rods can come out of the trim cylinders while still installed (to the piston)in the cylinder liner. You may unbolt the rods from the pistons, leave the pistons in the liners and remove the trim cylinder end cap, and replace the oring. Then reinstall the rod to the piston, insert the liner, push the rod all the way in to the liner and fill wit oil and tighten the end cap. This way you will not need the special tool to install the piston into the liner, and adding the oil will make the bleeding process much faster.

 

[fishdog4449]

Re: 76 mercury 115 tilt/trim

monk,
I recieved this engine for free this spring, rebuilt basically everything on the engine except the powerhead internals and trim system. It was a freshwater Lake Erie motor with very low hours, but had been sitting for many years.
Trim/tilt system worked fine when I got it and worked great for the first four or five trips to the lake. A few weeks ago (last lake trip), I started noticing a little oil leaking from around the rams when the boat was loaded down (enough to put the bottom of the trim cylinders in the water). At that time, I had just greased all the points on the engine so I attributed it to excess grease from the pivot points or steering tube.
I suppose I did suck water into the pistons when tilting the motor while the boat was loaded.
I've inspected the rest of the system very closely and I think (and hope) that only the rod seals are leaking. I'll replace those O-rings and test the solenoids and see where that puts me.

I have a spare working single-solenoid unit from my Merc80 just sitting around that I could use or borrow parts from as well.

 

[achris]

Re: 76 mercury 115 tilt/trim

There may be a little mis-understanding here... You only need one cylider to leak for the engine to go down. The hydraulic lines to each ram are in parallel, so if one leaks and loses fluid, and thus pressure, the other will also lose the pressure, and the fluid will flow to the leaking cylinder.

Fishdog, Are you aware of the manual release valve at the bottom of the trim pump to cater for situations exactly like yous? If you open the valve, then the engine can be moved up and down. The valve just allows the fluid to move around the system without the need for the trim pump to be running....

Chris.........

 

[fishdog4449]

Re: 76 mercury 115 tilt/trim

Chris,
Are you refering to the reverse lock or is there another valve Im not aware of?
I'm a noob at this trim system its the only thing I didn't touch on this engine.

 

[fishdog4449]

Re: 76 mercury 115 tilt/trim

Well ive been so busy with school and jrotc this is the first weekend I've had time to work on the boat. First thing I did was refill the unit with new oil, then tested for voltage at solenoids. Had 12v at both, so tried jumping between posts and the motor turned. Hit the trailer button and up she went. Huh?? Works fine up and down now. I'm at a loss to explain why it would start working again after I bypassed the solenoids just once.

 

[Chris1956]

Re: 76 mercury 115 tilt/trim

You could either have a deadspot on the motor or more likely, marginal electrical connections