SG4247

Hard to tell much from the pics, but here is what I would do:

1. Pull the spark plugs.
2. Use a stone and buff off the burrs on flange until it is flat. Put a dial indicator on the rear crank flange face and turn the crank by hand to determine if there is axial run-out on the flange (bent flange from the previous boom). It should be nearly zero. Maybe .001" - check the service manual for the spec.
3. With the same indicator, check the crank thrust end play with a pry bar. The clutch may have damaged the thrust surface on the crank. End play should be .005" - .008" guessing - check the service manual for the spec.
4. Turn the crank by hand, does it feel unusually tight in spots?
5. Drain the engine oil and check for main bearing material in the oil.
6. Inspect the flywheel bolt hole threads for cracks and hole elongation with a long bolt (3"-4" long) of the proper thread size and pitch. A good bolt hole will have a good fit and the long bolt wont wobble much when fully engaged in the treads. You can easily tell a good bolt hole from a bad one using a 3-4" long bolt as a gauge.

If all that checks good, put in a new clutch/flywheel that is precision balanced, using ARP hardware.

SG4247