1988 85hp Tilt/Trim Nearly Solved

[davijc02]

My previous tilt/ trim issue is nearly solved. The motor lowers itself as it should. However, when attempting to raise the motor I have another issue. While the trim phase is happening the motor sounds strong and operates as it should.Once the trim piston is fully raised and it begins to tile the motor the tilt motor just sounds like it loses all power and won't raise the motor unless you help it by hand. It did appear after a few attempts that the fluid foamed. Could this be the cause of my issues?

 

[scamp12]

I say Air in the system is it filled proper level . or you have a leak on your feed

 

[Jiggz]

You did open the system previously, so have you bled it? To do so you will need to cycle, i.e. lower and raise the motor for multiple times while ensuring it stays full of fluid. And yes, while bleeding it will require manual help to raise the motor fully but it should start to be able to do so on itself after a few tries. If there is no improvement, you might want to do the troubleshooting diagnosis again to see where the leak if coming from, tilt cylinder or valve body. I think in this case you can almost assume it is the tilt cylinder that is leaking.

 

[davijc02]

I left the motor in the full up position all night and it didn't seem to drop any. I've cycled it up and down multiple times.

The only other thing I can think of is the shuttle valve not being positioned correctly when I reassembled. I wasn't sure exactly how far it needed put back in
I assumed it would autocorrect as it moved back and forth.

 

[Jiggz]

The shuttle valve as long as the correct o rings were installed should center and positioned itself inside the "tunnel". However. since the the trim pistons rises all the way and when it is time for the tilt to rise the motor sounds it is struggling, then this could mean either the motor is underated. Correct me if I remember this correctly, but this motor and VB unit is a brand new unit, right? And it is one of those aftermarket Asian model, right? If you still have the old motor and VB unit, you might want to rebuild it and try it instead. If the problem persists, then you know it is not the motor or VB but more like the tilt cylinder.

The biggest clue I can see from your previous post is that the motor is "struggling" or seems to lose power when it is time to tilt the motor. Had this been a tilt cylinder or VB motor, I would say the motor rpm should stay the same and not slow down or struggle. Or had it been a valve problem not closing properly, the motor should instead increase in rpm instead of struggling. Just my 2 cents.

 

[davijc02]

Well....I think I have solved the issue. Unfortunately it seems like more work is gonna be needed. I have a pretty massive leak. The leak is located on the line that feeds the trim piston. There is a line that goes back behind it that I cannot see the connection but currently fluid is pouring down the backside of the boat from it. So possibly a hole in the line or the connector is shot? Im guessing an easy way to get to it doesn't exist...

 

[Jiggz]

You can always dismount the entire trim unit to get better access. The tubings for the trim unit are not as long and can be easily disconnected from the VB or both ends.

 

[davijc02]

Is it as simply as taking off the four star shaped bolts to remove the trim unit?

 

[Jiggz]

Can you post a pic where the leak is coming from? I really do not recommend opening up the trim cylinder unit unless necessary for those bolts are always under water and tend to be frozen and usually breaks when messed with. This is especially true if the boat is used in salt water. Use an inspection mirror & flashlight to find the source of the leak and if it is between the two pentagon halves, you will be better off dismounting the entire trim unit and do the repairs on a bench. However, if the leak is in one one of the fittings going into the trim unit, make sure they are not loose or worst yet crooked. Tightening tube fittings on this system requires to have both ends loose before you start tightening. You should always start threading by hand until you cannot turn anymore and then slightly tighten with a wrench (about one to two turns) and then do the same for the other end. Thereafter tighten both ends alternating on each end. Usually I do two turns on one end and then another two on the other end until fully tight.

 

[davijc02]

Jiggz,

The leak was located behind the trim piston housing. I took the trim unit down and found that the fitting came lose. I tightened it all back down and no leak occurred from that anymore. I did however have a leak where the valve body meets the electric motor. I think the oring wore from all the times its been taken on and off. also I had a drip on one of the lines on the side. Maybe it crossthreaded a bit. anyhow after reassembly the unit acted just as it did before. Trims with full power on the upstroke but when its time to tilt won't do it. I assisted several times to hopefully remove all air and made sure reservoir stayed full.

The unit performs awesome going down just not up. I still do have the old electric motor I however tossed the old valve body. I contacted the seller of the valvebody and they have granted me an exchange. So I will be doing that in the next couple days.

Now I'm considering putting on the old electric motor when the new valve body comes into rule out that as a problem.

 

[Jiggz]

It's disappointing you tossed the old VB. In reality, those old VB with proper replacement of o rings can outlast new Asian aftermarkets by at least two folds. Anyways, that is all water over the bridge for now. You are on the right track on trying the old motor. Hopefully, that will fix the problem.

 

[davijc02]

So my valve body has 3 lines going to the side and 1 on the bottom. If I want to perform the leake down test for the Tilt cylinder which line to I disconnect and cap? Which line would be disconnected and capped for the valve body test? I read the directions i'm just a bit confused.

 

[Jiggz]

No Title

To leak test the tilt cylinder make sure you have a cap for the tubings flare fitting and a plug ( see pics). Do the following:
1. Raise the motor to its full tilt.
2. Support the motor with a block of wood (usually a proper length 2X4 will suffice) and then relieve system pressure by tilting down a little bit.
3. Disconnect the tubing connected to the bottom of the tilt cylinder from the valve body. This is the most forward fitting amongst the three fittings mounted on the side of the valve body (see pics). Might want to wear protective goggles just in case or use shop rag to cover for possible oil spray.
4. Cap the disconnected line and plug the valve body to keep from draining the oil
5. Remove the support block from the motor
6. Mark across the swivel and stern bracket with a marker
7. Observe the marking for any indication of leak down. This may take hours but if there is a serious leak it will be indicated in a matter of minutes.
8. Any indication of leak down means the tilt cylinder needs to be repaired or replaced.

Explanation:
With the bottom tubing capped, with a properly working tilt cylinder the hyd oil has nowhere to go hence it should not move. However, if it moves then it indicates there is internal leak inside the tilt cylinder hence the hyd oil is passing through the cylinder's piston and o-ring and returning back to the top of the cylinder back to the top tubing back to the VB.

 

[davijc02]

Thanks Jigz! That explanation was as clear as the fluid I've been leaking. Lets assume this cylinder is bad. Do you know of a good place to buy a rebuild kit? I searched a little bit but came up with nothing. Or is it just easier to take it to a hydraulic shop and let them sort it out?

 

[Jiggz]

If the tilt cylinder is leaking, usually the first thing to do is to rebuild it by replacing the o-ring in it and then test again. If it continues to leak then it is time to replace it. There is an o ring kit you can buy from ebay which includes all the o rings for the tilt and also for the trim including some for the VB. There are also for sale used tilt cylinder that are fully operational.

Here's an old video demonstrating how to rebuild a tilt cylinder on an old Chrysler engine.

https://www.youtube.com/watch?v=JKpu6SpD5-E