compared to some of the drives I see locally, that is not bad corrosion. What you cant tell in the pics is how deep into the metal the corrosion has gone. Definitely not surprised the corrosion is near all the stainless metal.

I have dealt with outboards and outdrives sitting in the water on a monthly basis in all conditions in a commercial element in saltwater.

This is not normal degradation from lite corrosion .

This is serious stray current either from the boat or the marina or a boat nearby.

If others on this thread are observing this on their boats especially in freshwater you need to pull your boats .

A $10 multimeter easily and permanently mounted will show stray current present at all times.

OK, taking all that onboard, if one was considering buying the boat in the photos, does it look like a major concern?

Assuming the boat has been hanging with other boats and electrolysis is rife in the area, taking the boat away from the area relieves the immediate issue. Would you then think it just needs a good clean up, sand and re-paint or would it likely have gone deeper to internals?

To my untrained eye, it looks like surface corrosion that is easily repaired. The selling brokers believes it is just a cosmetic issue (no surprise there!). Based purely on the photos I've posted, would you think I'm right or wrong?

RR

Your pictures are crap, so tough to judge.

You never know with isolated corrosion .but that pitting looks fairly deep.

As some one mentioned earlier , getting the propshaft carrier out might get interesting.

Looks to have a solid spit of corrosion going on between the drive and the transom assembly also.

I had a gear case pretty much ruined in a week by a neighboring boat with a bad ground plugged into shore power .

Don't kniw I until you sandblast it if it is Swiss cheese

They're not my crap pictures, I am 8470 miles (by air) from the boat.... :)
Looks as though I'll be asking for some more detailed photos from the broker if a few other things can be resolved, price been the biggest factor...!!

Thank you all for your insight, I'm not afraid of taking a gamble but I like to know the worst case scenario before placing my bets.

RR

Interesting as the boats around me (both local and LOTO) look nothing like that. There is something seriously wrong with the boat's Mercathode system or it sits in water with a ton of stray current.

Where in the states is the boat?

Thought you just got out of the Frying Pan, now you are going to see if the Fire is any better with a used sterndrive boat?

It's in Ontario. Here ya go....
http://www.boats.com/power-boats/200.../#.WMa6Y5BXerV

Ideally prefer a single sterndrive or twin outboards but nothing is out of the question. My biggest issues are shipping/import costs and most of the boats I like are literally unsaleable in Thailand. Huge $$ loss on the Fountain so I'm going smaller and cheaper.

I'm also not very bright... :(

RR

Sent the link to a surveyor friend that lives in the city where the boat is to ask what would cause the corrosion and will let you know as soon as he responds

Thanks for that, any opinions are always welcomed.