If you have an electric clutch, you will have to use the alternator and regulator off of your old engine or if you purchase an engine with less than a 9 amp alternator. If you have a fuel tank or fuel pump mounted to your engine, you will also have to use it off of your old engine if you purchase an engine without one. If you have room for an engine with an oil filter, you can use one of the engines with one on it.