There is a special tool made to remove that 303804 seal. Lacking the seal puller, it is possible to use a ice pick to make a small hole in the seal on either side and screw a #6 sheet metal screw on each side of the crankshaft. It is then puled up going side to side with a nail puller. A length of PVC pipe the size to slip over the crankshaft will push in the new seal. . . 😉
