Is the engines top screen able to come off? If so there should be a bolt you can attach a socket to, take a wood drill bit and bang it into the socket, then attach the drill and turn it over. Also take the spark plug out. If it's frozen, PB blaster, WD40 penetrant or magic oil. Your choice. Then blow the lubricant out by turning it over. This is the only way to bypass a starter that I can think of