Motorguide stainless steel shaft corroding?

My 6 month old Motorguide Bulldog shaft appears to be corroding, although it is supposed to stainless steel. It looks more like aluminum that has come in contact with a caustic subsrtance. I'm not sure how to explain what I am seeing and hope the pictures better explain. It also looks like how some metals discolor when they have been heated up - although I am not aware of any issues. The motor worked fine yesterday. Always in fresh water, never salt.

http://www.earlysvilleironworks.com/link/mg_shaft.jpg

http://www.earlysvilleironworks.com/link/mg_shaft2.jpg

Has anybody seen a stainless shaft do this? I thought maybe it could be water getting up under some kind of clear protective coating but a closer inpsection doesn't look like this is the case. I don't recall any of my other boats doing it. I would call Motorguide but their customer support sucks.

Electrolysis is a possibility. Any corrosion or white deposits on the outboard lower unit (or the hull if it's metal)?

It is a result of current flowing between parts of the boat through the water. The fix is to connect a fused wire from the negative of the outboard battery to the negative of the TM battery.

It is a plastic hull boat

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Originally Posted by wasabi

It is a plastic hull boat

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It's most common to flow between the lower unit of the outboard and the TM. If the outboard isn't electric start, then all bets are off.

There is no outboard, just this trolling motor.

WAG here, but you ain't fishin around no docks with power on them are you?

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Originally Posted by J White

WAG here, but you ain't fishin around no docks with power on them are you?

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That's the next place I was going, so if it's a WAG, it's not too WA!

nope, no docks and no electricity in the pond. I do use it in other ponds/lakes but I can't see any of them having an issue with this such that it would cause this much corrosion.