Originally Posted by Fenlander
Re why the shaft seized up.. not sure how old your OB is but the general corrosion on your images is quite severe... looking more like a 30+yrs old OB. Image below is my 16yr old Yamaha 15hp showing the area near the gear shaft where all the paint remains in newish condition. I guess yours is an aux though which spends loads of time in heavy salt spray??
No it's not that old, it's from 2009, so just 10 year old. I bought it used three years ago with my 20 ft trailer sailer, of which it is the main engine. I've no idea how it was used or misused before that, probably the latter. It's always been used at sea, and I wouldn't be surprised if the previous owner left it all year long on the boat on a mooring.
Next thing I'm going to remove all visible corrosion, clean it up, and repaint it. I'm also going to fit a grease nipple on the level casing so that I can lubricate it properly every year.