Lower unit deteriorated on Johnson

[bikermikeyblack]

Pics are of a lower on my pontoon which has never been in salt water unit is 32 years old has a big hole in it and pretty much junk replaced with a rebuilt one any ideas what causes this terrible corrosion?

 

[bikermikeyblack]

Also now I am tilting the engine out of the water as after a week the new one is showing roughness on the paint

 

[F_R]

Electrolysis, for sure. By any chance, do you have copper anti-fouling paint on the boat hull?

 

[bikermikeyblack]

It’s on an aluminum pontoon boat

 

[bikermikeyblack]

In a slip at a large dock (50 boats)

 

[racerone]

Any body plugged into shore power in your area.-----Hurry contact your marina with the concern.

 

[bikermikeyblack]

The boat slips do have power that comes from the shore a few years ago code made them rerun it overhead instead of underwater

 

[oldboat1]

Looks like the zebra mussels have been scraped off -- combination of electrolysis and zebra mussels, I'd say. Actual erosion (holes) would be electrolysis. Keep the lower tilted out of the water when in the slip.

 

[bikermikeyblack]

Oldboat I’m now keeping it tilted for
Sure but didn’t in the past

 

[Faztbullet]

Someones boat around you had a bad ground

 

[bikermikeyblack]

Ok we have determined it’s electrolysis …for years I’ve been using a small battery tender 800 mah and I always unhook the positive battery cable does this have any bearing on the problem?

 

[bikermikeyblack]