Looks like a nice package. The boat's clearly had some use, but doesn't look a wreck. Not much info about the engine. Assuming you see no obvious faults and the seller seems straight, it looks like a reasonable purchase.
Most of it is common sense. Look at the places that get the most wear. Do they look worn? Are all the bits there? Does he have paperwork for the engine?
Interesting that he's photographed it the "wrong" way round on the trolley, and without the engine in sight. Is he selling it for someone else?
Do not pay before you've seen it with your own eyes at the place of purchase. A common internet scam is to post a "poached" picture of someone else's item, try to get a deposit or full payment up front, then disappear.
For comparison: I play concertina, and I have often seen the "same instrument" (i.e. the same photo of an instrument) in adverts numerous times.
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