Buy a Kill-A-Watt meter. MCM Electronic has them. Plug the Kill-A-Watt into your generator and set the engines RPM to about 62 HZ unloaded. Put a load on the generator, A electric bath room heater works good. With the load on the generator adjust the main jet on the carb. for the smoothest running of the engine. Idle mixture is not much of a concern on a generator engine.