MERCATHODE - Bravo3 wires jammed

Been helping a buddy, a new mercruiser owner, get acquainted with his older engines and drives. One of his Bravo 3’s had a cruddy looking mercathode - when he pulled it, the wires were corroded and severed at the hydraulic ram manifold ( where it feeds up into the transom mount and into the engine compartment ). The access from inside is literally undoable and of course the manufacturer tacked the wires to the transom - you can see it but cannot get to it.

when trying to push the wires up from the outside, they don’t budge - even with an awl.

questions:

how the h*ll should I attempt to remove the old mercathode wires when there’s no access from the bilge and the wires are corroded in place at the hydraulic ram hose manifold ?

if we remove the hydraulic ram hose manifold, where the mercathode sits, from where it mounts, will this help and, will hyd fluid leak ?

Mercruiser makes a mercathode system with transom mounted pucks given your access issues you could likely buy the pucks put them on either side of the transom housing and go through the transom higher up above the water line with the wires

Good point. That might be an option after I’ve exhausted trying to get these wires out. I assume water got into the home where the wires ran from the mercathode up, corroded the wires into place. There has to be a way to get these wires out and run new ones through.

Any unusual corrosion or discoloration of the props?

abl1111 said:

Good point. That might be an option after I’ve exhausted trying to get these wires out. I assume water got into the home where the wires ran from the mercathode up, corroded the wires into place. There has to be a way to get these wires out and run new ones through.

Click to expand...

There is a way but usually requires a skinny young guy with small hands ...aka not me.

I would second Chris's comments on corrosion - my buddy with a B3 has had his lower housing and now gimbal housing corrode - he had a failed mercathode and a lot of stray current in his marina. ended up adding a mercathode with the pucks in addition to the original mercathode under trim manifold housing

I'd like to fix it right, but can't think of a way to get those wires out ( up, in this instance ). This drive looks clean. The props too. I thought of sealing up the hole where the wires go, or just reinstalling the bad mercathode to seal it up and leave it as is.

It's obvious the mercathode for this engine has not been functioning for quite a while. If there was active corrosion, it might be a much more pressing issue.

As for the Skinny Guy ( I'm not that ) - I could fit my body into the only place to access the wires, but where the wire is nailed to the transom is beyond any hands reach. #@$@%$& ridiculous how production boats are built !

If the boat is on a trailer, Mercathode is not required. The purpose of the unit is to reduce galvanic corrosion. If the boat sits in the (salt) water all the time, and there is stray current from the marina's electrical system, then there is the possibility of the drive being eaten away by the electrolysis.
Your best defense is to check the sacrificial anodes regularly. This is far more important than the Mercathode

Stored in salt for 5 months.

Understood. I’m just a stickler for mechanical things being as intended... Annoying that I can’t think of a remedy to get those wires out.

As an aside, if the hydraulic trim hose manifold, where the mercathode mounts to, is removed, will hydraulic fluid drip everywhere - or is this a contained unit ?

The manifold drops down the hoses from pump to the manifold will drop down with it.

If you can get the trim mani loose then you'll have a much easier time winkling in new wires for the Mercathode. Stiff fishing line or trimmer string will help act as a wire fish.

Ok do manifold housing is self contained.

o2 - nothing will fit into that area until those old wires come out. And, due to these same wires being screwed onto the inner transom in an inaccessible place, you can’t cut them to pull down from manifold area. Could be why previous owner never changed the old mercathode ?!

FYI, No unusual corrosion, props are not discolored and has not been working for a while? Disconnect the power from the Mercathode generator and Abandon the system...

^^^Agree with Chris ^^^