Would you have the model # of the Kohler? I am in need of a new one to replace the eh65 22hp. How did the Kohler swap work out? ThanksThat's what i ended up doing. Bought a Kohler, but the shaft was larger than the Robins, then i found another Kohler, after i put mine in, that had same size diameter shaft as the Robins engine. I talked with Terry and he sold me a "kit" that i used some of the parts out of, to adapt the Kohler. Stepped me up a couple HP, and less noisy. Probably the best upgrade ive done to the 422.
I would connect it to the engine. Small amount of resistance counts when powering a starter motor. I am only an electrical engineer, but do have experience with starters.Normally either will work as the engine should be secure to the chassis. What is important with a ground is that stays solid and is ideally located away from modules in case of voltage surges IE from jump starting as an example. You can always run a ground to both the chassis and engine.