tilt/trim hydraulics are slow and sometimes stuck

[brettule]

I've got a 1978 Johnson 85 HP (85ETLR78C) which gets regular annual servicing by my marine mechanic. Last was only 6 months ago but it's developing a bit of an issue which I was wondering if anyone recognises?

After the boat has been sitting for a few weeks it struggles to tilt all the way up for transport. I can hear a popping sound, perhaps a little like air bubbles, as it struggles to lift the engine. The electric hydraulic motor works fine, it rev's as usual, it's just the rams don't move quickly. Eventually it does lift, but once it's up it won't come come down. Once again the electric hydraulic motor spins but the rams don't move. If I leave it for 30 mins and try again it does come down.

Q1. Does this sound like any text book problem? Low hydraulic fluid due to a leak? Air bubbles in the system?

Q2. How I bleed the system to remove air bubbles?

Cheers

 

[RRitt]

Re: tilt/trim hydraulics are slow and sometimes stuck

IMO, it could be low fluid, binding pivot, or both.

Your reservoir is generously oversized. In order to run low on fluid it would need either a pretty noticeable leak or a very long time without checking level. Examine top of rams, manual release fitting, and trim sensor fitting for oil leak. If no leaks then rams probably okay. If leaking, still does not exclude ram binding but does indicate need for ram rebuild.

 

[Joe Reeves]

Re: tilt/trim hydraulics are slow and sometimes stuck

I've got a 1978 Johnson 85 HP (85ETLR78C) developing a bit of an issue. Sitting a few weeks, it struggles to tilt all the way up. I hear a popping sound, like air bubbles, as it struggles to lift the engine. The electric hydraulic motor works fine, it rev's as usual, it's just the rams don't move quickly. Eventually it does lift, but once it's up it won't come come down. If I leave it for 30 mins and try again, it does come down.

The unit is self bleeding. The reservoir must be full to the overflowing point when the engine is in the extreme tilted up position. (Check it!)

The fact that you can leave it for 30 minutes, then it does function indicates a Oil Pump check valve problem as follows.

(PTT Temporary "Down" Lockup)
(J. Reeves)

A problem that takes place in various PTT units is that a boater will trim the engine all the way up, then attempt to trim it down, only to hear the PTT electric motor running and nothing happening... the motor is not moving downward. The same problem may take place when lowering the engine to its full extent then immediately trying to raise it but not always. Then, after waiting a short time, the boater finds that the PTT unit is functioning properly once again.

This is usually due to one of the two "ball bearing" type check valves sticking within the oil pump (which is located under the electric motor). At least this is what I've found to be the case in every instance I've encountered this problem.... and it is usually the blocking "ball" check valve pertaining to the "up" mode.

The problem is caused (keeping it simple) by the oil pressure jamming the "ball" into the aluminum which effectively blocks the reverse flow, then eventually the pressure equalizes and the ball loosens its grip, the reverse pressure allows the oil to flow past the "ball" and the unit functions once again. Many boaters, aware of the cause, simply live with the problem. However, the cure has always been to replace the oil pump.

 

[RRitt]

Re: tilt/trim hydraulics are slow and sometimes stuck

i dunno joe.
He says it lifts slower and makes a popping noise. Sticky flow valves won't cause that. In my experience, sticky flow valves usually happen when the pump continues to run after the system is fully raised. It is the extra pressure of driving the engine up into its mechanical stop that gets the ball wedged into socket. In my experience, if you don't over-lift then you don't get pressure lock.

 

[brettule]

Re: tilt/trim hydraulics are slow and sometimes stuck

turned out to be low hydraulic fluid, must be leaking from the seals. Is it a difficult job to replace the seals?

 

[RRitt]

Re: tilt/trim hydraulics are slow and sometimes stuck

turned out to be low hydraulic fluid, must be leaking from the seals. Is it a difficult job to replace the seals?

not too difficult if trim sensor isn't leaking. If trim sensor leaks then water can get inside ram and cause rust. It can be time consuming to repair the rust damages or expensive to replace the parts. seal kits are cheap. ebay or dealer should have them.

 

[brettule]

Re: tilt/trim hydraulics are slow and sometimes stuck

is there some sort of generic seal kit I should look for online which suits my motor

 

[boobie]

Re: tilt/trim hydraulics are slow and sometimes stuck

RRitt, trim sensor on a 1978 ???

 

[RRitt]

Re: tilt/trim hydraulics are slow and sometimes stuck

one of the two rams on the old dual ram systems has a coil of wire inside the ram. The housing has a terminal post about halfway up that contacts the windings. As the ram lifts, the resistance to ground will change. By design it should be able to display the exact angle of engine during trim cycle. I have no idea what OMC actually does with the wire.

The fitting sometimes leaks and the insides of ram rust up from water.

 

[RRitt]

Re: tilt/trim hydraulics are slow and sometimes stuck

is there some sort of generic seal kit I should look for online which suits my motor

0172575

https://www.google.com/search?q=017...57&sourceid=chrome&espv=210&es_sm=93&ie=UTF-8

 

[boobie]

Re: tilt/trim hydraulics are slow and sometimes stuck

I do believe the '78 has integral tilt and trim.

 

[RRitt]

Re: tilt/trim hydraulics are slow and sometimes stuck

thanks, I did not know it went back that far. Do you know the earliest year?

 

[brettule]

Re: tilt/trim hydraulics are slow and sometimes stuck

0172575

https://www.google.com/search?q=017...57&sourceid=chrome&espv=210&es_sm=93&ie=UTF-8

Thanks. I bought this kit: http://www.**********/parts/detail/brp/B-0172575.html

 

[boobie]

Re: tilt/trim hydraulics are slow and sometimes stuck

RRitt. Go to shop.evinrude.com and look up the mtrs. In 1977 the bigger ones had the integral t/t. Hope this helps. In1976 the 200 hp had it. That was the first year of the 200 hp V-6 cross flow.

 

[RRitt]

Re: tilt/trim hydraulics are slow and sometimes stuck

Thanks. I bought this kit: http://www.**********/parts/detail/brp/B-0172575.html

i might have given you the wrong part # for your system. that part number is for the system in this picture
Rebuild KIT Evinrude Johnson 1972 1989 Tilt Trim Cylinder Seal 0172575 QUAN2 | eBay

if that is your system, then you would need two of the OMC part number. One for each cylinder.

I can not locate a single part number for the other integral system. From parts listings it looks like you have to order than all individually. Maybe boobie knows of a kit?

 

[boobie]

Re: tilt/trim hydraulics are slow and sometimes stuck

I looked and it looks like you have to buy individual parts. Couldn't find a kit either.