Corrosion on extension F250 TURD

[Grouper Genius]

Looks like corrosion from inside out. I think it's just an extension but not sure. 2005 motor.

[Grouper Genius]

Here's a pic.

[robert graham]

I'd take a knife or pick type tool and lift that to see what's underneath....could be an old crack or damage that was repaired with JB Weld or similar epoxy filler and it's coming off....in any event you can repair with JB Weld, file, sand and spray paint...

[TownsendsFJR1300]

It is an extension to make the engine a long shaft.

Part #53; 2005 F250TURD Yamaha Outboard UPPER CASING Diagram and Parts

[rodbolt17]

looks like corrosion is cracking it or some water was trapped and froze.