If you think how many eBay members there are around the world, then how many engines they pretended to have sold. They would have sold many thousands perhaps as it was very cheap and lots were tempted. Not everyone will open a dispute and claim their money back. Which then leaves lots of money left in the pot for the scammers... an old trick really.
Also, eBay/Paypal have refunded us, they now need to reclaim their $ from the seller. Not sure how easy that will be, for a disappeared Chinese seller.
Something a bit similar about 10 years ago on ebay. Someone set up an ebay acc selling cheap ($1 to $5) coins. Got their positive feedback up then listed a heap of expensive high grade collectable coins. They were located in Malaysia so postage took 2 to 3 week to USA, Australia etc. After 2 weeks they shut up shop and disappeared.