Recently I was insterested in purchasing a Craftsman 6.75hp lawn mower at a Moving Sale. Asked owner if it would crank. He pulled the crank a couple times, pumped the primer about 3 times, pulled the crank again and INSTANT START. So, I bought it. About a week later I tried to crank it. Pulled crank 3 or 4 times; pushed primer 3 times; pulled crank several more times; again pumped primer 3 times; and still no crank. It has gas and oil, but very little indication of compression when I attempt to crank, but cranked relatively easy for former owner. Any suggestions.

Sounds like you flooded the cylinder with gas .
Pull spark plug out , pull over a few times with spark plug out.
Install plug , put on full throttle no priming pull until it starts.
Luck

THANKS, DG! Will give 'er a try. 'Fraid I don't understand 'chinery.