Looks great!

You could drill it out a bit and put in a bigger roll pin. Or you could ditch the roll pin and use a stainless nut & bolt. Another thing you could do is bore it all the way through and thread the end of your shaft for a lock nut.

There is a slight learning curve to operating one of these deals. First, set your idle speed a little bit higher. I set mine with the prop in the water. This will keep it from bogging or dying when the prop hits the water. Let it warm up before you try to take off. Mine usually needs a few minutes or it tries to die when you give it gas (even out of the water). Don't use full throttle. Your engine can run about 7000 RPM while the prop works best at about 2500 RPM. Turning the prop faster will not make you go faster, it just starts to bog the engine down. Experiment with throttle position and you'll find the "sweet spot" is usually somewhere between 1/3 and 1/2 throttle. Also, did you bypass the clutch making it direct drive or did you leave the clutch operational? Mine slipped considerably under load and melted the plastic housing on it's trial run all those years ago. Bypassed it and never had a problem again.

Another thing to keep in mind is to tip the prop out of the water for 1/2 a second occasionally. As you kick along the engine sometimes starts to load up, you can feel it and hear it. Just tip the prop up very briefly and keep on moving. Do the same thing when you start to encounter weeds. Do it when weeds first start to wrap on the prop. If you let them wrap up it will kill the engine, but if you keep tipping it up as the start to wrap they will be thrown free.