If it's frozen from sitting, you might try this... Set it down so the spark plug hole is UP. Remove the spark plug and pour several tablespoons of light oil, or kerosene into the spark plug hole. Let it sit at least overnight, maybe a couple of full days. After it has sat, try to put a wrench on the big flywheel nut and S-L-O-W-L-Y attempt to turn, by rocking loose. If you get it to turn freeley, proceed from there. It is in all likely hood a Tecumseh powerhead. If so it takes, a 24:1 oil to gas mixture. try certified parts corp for parts and maunal.