Before you do this, let me tell you from experience that roto-starts suck almost as much as pullstarts. You will be replacing the one way bearing and the shaft every gallon of fuel, and they are like 40$ for the two pieces. The backplate for the roto-starts break off, and you have to buy new ones. the roto-start units are either too powerful, or too week. The batteries last about 10 minutes. IT WAS A FREAKING NIGHTMARE!! not to mention that your engine will get better milage, make more power, higher RPM's, and lasts longer with a bumpstart backplate...Invest in the starter box, you will thank me in the long run, and you will save a fortune!!