If you did leak gas into your cylinder, you would have to take the spark plugs out and kick it over. Yes, you do need a special puller for the rotor, easy to get on ebay, or I've heard you can use your rear axle(same thread). If you hurt your gasket you will have to replace it of course, I use gasketcinch to hold the gasket in place. Inside your starter clutch are three rollers, three spring caps, and three springs, the rollers need to be checked for flat spots along with the surface of the starter gear which they roll on. If your starter motor needs help, Rick's motor sports electrics can re-build that one for you or sell you a new one. They are located in New Hampshire and are great to deal with!