Hello and welcome to Just Answer,
I assume you are wanting to remove the pulley from the bottom of the engine. If I am correct then the first thing to do is remove the bolt from the bottom of it. Once you have the bolt out you will then want to try to tap it down off lightly with a hammer. If it will not vome down then you will need to purchase a 2 jaw puller. If you are having problems with the engine turning when you try to loosen the bolt then take out the spark plug. Get a clean piece of rope about 1/4" diameter about 3 feet long. Put about half of the rope in the plug hole and it will act as a piston stop to keep the engine from spinning.