You might remove the spark plug and then see if it'll crank.

Next, I'd remove the valve cover and see if there is obviously something amiss.

Thanks. I removed the spark plug, gave it some more oil and was able to get the flywheel to turn and eventually turn over. I then cut half of my yard. I was pulling it back in when I heard a pop/snap and the motor just started spinning.

Now when I try to start it the motor spins normally but never turns over. I replaced the spark plug thinking that was the issue but it still won't work. Again, I turn the key and the flywheel spins, just doesn't turn over. Any thoughts?

Thanks!

"when I heard a pop/snap and the motor just started spinning. "

What do you mean ....."just started spinning"?

You might remove the spark plug and with a pencil or similar and slowly crank the engine by hand and see if the piston is moving up & down.

If it was the 20 hp Briggs single cyl, I have one eight years old also just a cutting along one day and it locked up no noise no smoke and a month later its still locked up I'm going to replace it with a 17.5 Briggs they had a lot of trouble with that engine. Its going to cost me a little over 400.00 for engine and oil and filter