I bought a old Honda 4.5kw generator that had a blown engine. It was one of those really old units that used a belt between the engine and the generator.
I have a
f2000 kubota mower with a 72" deck. I wanted to use that to power the generator. A long time ago the
Surplus Center had mower deck driveshafts and one of them plugged right into my pto. I took the blown engine off, used two pillow block bearings and a shaft with brackets and mounted all that in place of the blown engine with a new belt.
Then came the calculations for rpm. First off, my engine is 20hp. This generator would not need all that horsepower, and I didn't want it screaming at high rpms constantly wasting fuel while running the generator. With the 72" deck still on it, I played with the rpms to see where the best spot was were the engine seemed to have power and the governor could kick in when it needed. I found I could run the engine at about 1600rpm, and it still seemed to react ok to a load.
I then measured the pto speed, and in high, the pto speed was exactly the same as the engine speed. The specs on the honda generator called for 3200 rpm for 60hz full output operation. So I knew I needed to double the speed of the shaft I installed.
I measured the pulley diameter at the generator, and it was 5 inches, so I knew I needed a 10 inch pulley for the drive. I called some local places and they wanted right much money for the proper pulley, and by the time I paid shipping from the
Surplus Center, it would have been close to the same price. So I went to tractor supply, they have those universal pulleys where you weld in the hub. All they had was a 12 inch, so being cheap I bought it.
Theoretically the 12 inch is too big,, but in reality it works ok. I still run it at around 1600 rpm, and when a load is put on it, the tractor slows to about 1450-1500rpm. It seems to work fine, I have used it already during one power outage. And with the 5+ gallon tank, it should run a long time like this without needing re-fueling.
