Power trim failure

[Sunburn71]

Hello all, I am new here but wanted to share!
I recently had a failure of my power trim which I thankfully discovered BEFORE getting on the water. I noticed that the drive was not in the fully up position as I was removing the boat cover. When running the drive up the pump was running at a high speed and the drive didn't move at all. Oil came out the back of the boat from the bung hole at the transom. After going through a few of the stages of grief, I figured out my problem and figured I would share to help others.

 

[Sunburn71]

So I removed the manifold/ coupler from the transom and found that a line had come off the manifold due to extreme corrosion of the manifold. As you can see from the picture, there were no threads left for the line to bite into. This likely failed at the dock when pulling the boat out at the last use.

 

[Sunburn71]

The Mercathode electrode assembly was corroded into the manifold and was wrecked beyond help. I ordered up the parts and dug into replacing them. What a crappy job that was! Hot ,sweaty, misery! The area where the wires run is extremely tight under the exhaust and required some creativity to do. One thing that might help others was to butt connector a wire to the old wires and pull up from inside. Use the wire to attach (with tape) your new electrode wiring and patiently pull through to the inside. This took forever!

 

[Sunburn71]

One question: I checked for voltage at the Mercathode module and have 12 volts on the red wire and the orange wire. I did not measure any voltage between orange and brown, what is the expected result?

 

[tank1949]

Your example is why I never store an IO wet in saltwater. I snatched my Mercathode off the ODs while working on my boats restoration process. I have owned 6 Alphas/Gen## and now Bravos and corrosion is the acheles heal for all MCs IOs. I am surprised OD area is not just as corroded as your Mercathode. You should be able to find important info from this page: https://sterndrives.com/galvanic_corrosion.html

 

[Sunburn71]

Thanks for the link. I have always trailered my boat so corrosion in the future shouldn't be a problem. The worst part of the corrosion was inside the boat strangely enough.

 

[Sunburn71]

Thanks for the link. I have always trailered my boat so corrosion in the future shouldn't be a problem. The worst part of the corrosion was inside the boat strangely enough.

 

[Sunburn71]

Sorry for the double reply, using the forum with my cell phone is a bit clunky...haven't figured out how to delete. D'oh!