Merc 888 - Phantom trim leak

[Dave_A]

Ok...

Simple enough - I've gotten all the other stuff on my boat working, EXCEPT for this $!%#$ trim leak...

The problem? Well, the trim rams & pump work fine, the drive goes up & down...

But cycling it through one 'up' and 'down' motion results in dumping an entire res full of ATF 'somewhere'....

I believe I've isolated the problem to the 'down' circuit, as the 'UP' circuit pressurizes & reaches it's limit easily, the 'down' is sluggish as hell even with a full res...

I have one opaque plastic hose coming out of my pump, and one fabric-coated hose - I think this means that the 'fabric coated' hose is OE or close to it, and the plastic one is a replacement....

I see ATF in the bilge water, but can't quite figure out where the leak is...

Is there any way to replace the hoses without pulling the engine?

 

[Bt Doctur]

Re: Merc 888 - Phantom trim leak

Most likely you have an older system with the "reverse lockout"
not adjusted properly will cause a hose to rupture.You should have a plastic hose to the lockout and a fabric one going to the drive

 

[Dave_A]

Re: Merc 888 - Phantom trim leak

Is the lockout a big black cylindrical thing mounted on the transom, directly behind the engine?

If so, that's exactly where the plastic hose goes....

That hose appears to be intact...

I assume the fabric hose feeds both 'in' and 'out' movement...

This is a 'single solenoid' unit on a 1975 boat.....

Is there any easy way to get at the hoses that are down in the bilge well?

 

[Bondo]

Re: Merc 888 - Phantom trim leak

But cycling it through one 'up' and 'down' motion results in dumping an entire res full of ATF 'somewhere'....

Ayuh,... With a leak that Severe,... It shouldn't be too awful Hard to find,...
Have somebody cycle it while You Look...

Is the lockout a big black cylindrical thing mounted on the transom, directly behind the engine?

Yes...

I assume the fabric hose feeds both 'in' and 'out' movement...

Nope,... Only the Hi-pressure side...

Is there any easy way to get at the hoses that are down in the bilge well?

Ayuh,... They attach to the Hyd. Manifold, bolted up from the bottom of the drive, Outside the boat...

 

[ziggy]

Re: Merc 888 - Phantom trim leak

the reverse lock valve is the disc looking thing that is actuated by the shift lever. the drive unit shift cable and the remote shift cable attach to this shift lever that operates the reverse lock out valve.. it's by the shift plate.
the hoses that disappear, if they're like mine. there's a manifold on the outside of the boat. ya take the manifold off and on the back side that ya can't see, is where the up, down hoses from the trim system go to.

i think the big cyl. looking thing yer talking about is the trim sender.. (about the size of a small corn on the cob)(i would think that being from nebraska ya know. )

 

[picklenjim]

Re: Merc 888 - Phantom trim leak

The manifold they are talking about is the block outside that all your trim cylinder hoses are connected to.Remove the 2 nuts and pull it straight down.You will then see the lines from inside the boat are connected to it.Remove 1 at a time and tie a string to it.pull it up into the boat.Then tie that string to your new hose and pull it up from the bottom into the boat.You probably are going to have a lot of fluid come out when you remove the block.I see you mentioned you are using ATF in your system.I know people that do and I'm not trying to tell you what to run but the Mercury manuals call for 10W30 or 10W40 Motor Oil.