Tilt/trim leaks down overnight

[Dave1027]

If I do not support the motor with something and I have it tilted up, the next morning it has moved down by itself. I'm assuming it means a leaking seal in the hydraulic piston. Is this what it is or is it a leaky valve? Is this common? What can be done? Can I run some stopleak fluid in it?

 

[RRitt]

Re: Tilt/trim leaks down overnight

what year and horsepower. Or, even better, a picture of your trim system.

that aside - probably a leaky valve and stopleak or seal softener does more harm than good. The manifold passageways on a lot of mercury designs can't be directly accessed and if the sludge is too thick or stubborn it can cost hundreds to fix.

 

[Dave1027]

Re: Tilt/trim leaks down overnight

'88 100 hp Mercury inline 4 cyl. It has one large piston for tilt and two small ones for trim.

 

[RRitt]

Re: Tilt/trim leaks down overnight

probably the pump. part #24 in diagram
http://www.boats.net/parts/search/M...TS(THREE RAM POWER TRIM DESIGN II)/parts.html

 

[Dave1027]

Re: Tilt/trim leaks down overnight

Is it possible it could be something simple like the manual release valve loose or leaking?

Is #13 on the diagram the manual release valve? Can I take it out to inspect? Maybe replace the o-rings? Would fluid leak out if I remove it?

 

[njrextreme]

Re: Tilt/trim leaks down overnight

Is it possible it could be something simple like the manual release valve loose or leaking?

Is #13 on the diagram the manual release valve? Can I take it out to inspect? Maybe replace the o-rings? Would fluid leak out if I remove it?

Have some one push down on it w/ the motor up. Look for leaking fluid. What does the ram look like. Is it all black and oil filled? Could just be the seal on the ram.

 

[Dave1027]

Re: Tilt/trim leaks down overnight

There is nothing leaking even if I push down on the motor. Fluid is full. I'm thinking a o-ring or seal is leaking. What is the ram? Is it part# 3 in the diagram?

I'm thinking the O-ring kit (part# 18) might fix this. I'll do it next off season.

Rritt, the pump still pumps perfectly so how can it be bad to the tune of $450? Could it simply be a leaky o-ring or seal in it?

 

[RRitt]

Re: Tilt/trim leaks down overnight

Mercury does not sell the oring separately. it won't be manual release. The manual release makes a seal by its location rather than by being tight. It doesn't even need to be finger tight to work - just seated.

Bleed down is 99 out of 100 times the pump check valve. Which 100 out of 100 times mercury does not sell seals for and only occasionally will they sell the check valve assembly separately.

 

[Dave1027]

Re: Tilt/trim leaks down overnight

Thanks Rritt. I guess Merc really has me by the nads then. Any recommendations on what I should do? Can these units be had for less than $100?

 

[RRitt]

Re: Tilt/trim leaks down overnight

examine the parts diagram and see if your particular design can be repaired with unit still mounted to boat. If not, the first decision box is whether or not it is worth fixing.
If it can be repaired without taking engine/transoms loose then then drill down into parts diagrams to find the forward check valve. Try as many different parts diagrams and engines as you can find. Sometimes the same system has better parts diagrams when mounted onto a different engine. If you can get a forward check valve then it should fix your bleed down.

 

[Jacket4life]

Re: Tilt/trim leaks down overnight

I don't know how they did it, but I had a friend who had one rebuilt at a hydraulic shop in Dallas. I think he pais $150 or so. That was three years ago. Hope that helps, I know I'd at least check into it before I pluncked down $450 for a new one.

 

[RRitt]

Re: Tilt/trim leaks down overnight

I don't know how they did it, but I had a friend who had one rebuilt at a hydraulic shop in Dallas. I think he pais $150 or so. That was three years ago. Hope that helps, I know I'd at least check into it before I pluncked down $450 for a new one.

Eaton has four repair centers located around US. If you took your system off boat and took it to one of their centers then that sounds about right for seals. It sounds too light in the wallet to include any mercury specific parts like manual release valves, bearings, bushings, die-cut seals, or trim motor.

 

[Dave1027]

Re: Tilt/trim leaks down overnight

I could live with the leak down problem because I store it in the trailer jack. The problem comes when I'm boating and am trimmed out, it trims back in by itself. I have to keep trimming it out.

I have the service manual for my motor. It specifically says the pump is not serviceable and must be replaced as a unit. I saw a compatible unit for sale on ebay for $150. I might get it. It's part# 44 in this diagram.

 

[RRitt]

Re: Tilt/trim leaks down overnight

yup. in the pump somewhere is a $0.05 oring that wants to die. I think mercury used to sell a pump kit full of orings and valves for your system but withdrew it from market. I've seen those pumps on Amazon, google, and ebay for $150ish. Not worth the hassle of installing a $100 mercury kit if you can get new for that. The cheap ones are probably chinese and probably won't hold up for another 20 years but at that price you can buy a spare.