If you are in need of a Honda GX160 engine eBay is probably not the best place to look. The problem is that these engines are used on go-carts (or Karts as the enthusiasts like to call them). Both in the auction and at the racing track there is keen competition for these engines. Used plant engines are likely to have low compression or be caked in cement or both! Generator engines are a better bet but have tapered shafts. A further problem is transport and petrol. The worst case scenario is when the seller leaves petrol (or even petrol fumes?) in the tank. The engine gets picked up by the courier but then gets held in limbo at the couriers depot. In such cases there is a grave risk that the engine will eventually dissappear.
My advice is to purchase a NEW Chinese copy of a Honda unless a genuine Honda is needed for homologation reasons. You see there are too many people using eBay as a dustbin that gives them money, and too many young dudes with go-carts. Incidentally engine weight is only 13 kilos so GX160s can be shipped by Parcel 2 Go quite cheaply. One named brand of Honda lookalikes is Loncin but there are other un-named brands as well. Prices are about 1/3rd of Hondas.