I believe my motor seized up due to excessive heat. The funny part was it was running and I shut it off to let it cool down and it would not start again. I was able to turn the flywheel with a cheater bar,l but it turns hard. So far I have pulled the spark plug and sprayed penetrating oil into it and replaced the plug, it is now sitting for awhile. I plan to try to turn the flywheel again and repeat spraying. If this does not work is there anything else I can do? It is a Murray 11hp engine.

Leave the plug out while trying to get the motor to move, that way you will have less resistance.