Think I should buy this?

[chesapeake724]

Ahoy, gents.

Ever since the prognosis from the mechanic about my Johnny 175 (runs well, holes and pistons are clean, compression even, ignition wires could use preplacing, cooling water leaks, exhaust leaks, could run forever, could die the first trip) I've been keeping an eye out for a cheap replacement. This was posted on fishing board I frequent:

'86 Yamaha 200
2 cycle outboard. Excellent condition. Runs great. Low hours. All controls and oil injection tank included. Repowered boat with new 4cycle Yamaha. Asking $500.

I got an email back that everything is in good or better working condition. The guy that put up the ad and the guy selling it have army.mil email addresses, so you'd think I can trust 'em. I mentioned it was odd that the dealer didn't just give him the $500 and took it in trade against the 4-stroke, but the dealer didn't want such an old motor.

I'm thinking for $500, I could probably get rid of it without losing much if I come to find out it's not reliable enough to hang on the transom. Worst case, I'd part it out and make the $500 back, so I'd only be out the hassle, but not out any money.

Any thoughts?