I just thought I'd add to this one. I have had the 13hp "Honda" for quite a while now and, after a few of MY errors (fuel system) and getting it worked out, it runs great. It has a lot of low end torque and likes to rev. I have no complaints about it since the problem it had was my fault.
I hooked the fuel pump from the Kawasaki up to it and, it being a gravity feed, flooded like crazy. Now that I hooked it back up to gravity feed, it runs great, and has more power (probably because it's not in a constant state of flooding. If I had it to do over, I'd buy another "Honda" since it's the exact copy of a real Honda and it's cheaper by around 4-5 times.
The only thing I would do differently is to get the 16hp instead of the 13hp. This engine hasn't ran out of power yet, but you can never have too much!
It doesn't knock, rattle, ping, pong, shake, or quiver, it's actually smoother than a genuine Honda GX340 that I use. I'd recommend it to anyone looking for a cheap upgrade!
The only differences now are that I put the stock muffler back on it and I re-did the throttle linkage. I'm pleased!