I used to have a Champion outboard. Does yours have 3 - 1/4x20 screws or bolts mounting the starter to the flywheel? If it does, like mine did, find a piece of 1/4' flat stock, and drill 3 -5/16' holes to match the patern on the flywheel. Loosen the flywheel hold down nut until it is flush with the end of the crank. Lay the plate on top of the nut, and determine how long the bolts have to be to bottom in the holes in the flywheel. Buy new all thread bolts 1' longer, and install a nut, run all the way to the head of the bolt. Install the bolt assembly thru a washer and the 1/4' thick plate, and lightly bottom in the flywheel. Next, back off on the nuts, until they just contact the plate. Now back off each nut 1 additional turn, and give the center of the plate a sharp rap with a hammer. The flywheel should now come loose. You may have to repeat this again. If the flywheel does not pop free after the second attempt, try putting some penetrating solution on the crank, and leave tension on it overnite. Once the flywheel pops loose, remove the plate, and remove the hold down nut from the crank. The flywheel should be sitting on a tapered shaft end. NOTE : the end of the crank is relatively soft - do not beat on it excessively. the screws on the puller do most of the work, all you want to do is set up a shock wave to bust it loose.
Andrew