Looks like a Honda GX35. The blue box is a right angle gear box, I assume with some degree of reduction, and then chain drive to the left side. Also it looks like the builder used a weedwacker clutch to connect to the gearbox, why I am not sure but probably because that was the easiest connect to that box or maybe that was what he had on hand. DIY all the way.
There are simpler ways to do this I think with less power lost than the right angle box.
