MTD ridding mower accidentally hit a root [ separate problem // the devise once in motion will not stop] & engine strained then stalled. When restarted ran with no power but did get under cover. Next day will not start; has spark;added fuel to carb & no start; removed fly wheel & no damage or misalignment of key way. Removed valve cover & vales move when flywheel hand turned. Valve gap is with in specks & push rods not bent. Removed head & don't know if gasket is bad.
Any help greatly appreciated.

It really won't matter now once you removed the head you have to replace the gasket with a new one. What do you mean " the devise once in motion will not stop"

What is with the negative rating on my answer? You said you didn't know if the gasket was blown and it doesn't matter. Once you pull the head you can't reuse the gasket and must get a new one. The rest of your rating reads ".[belt adjustment prob caused the machine to always be moving/no fast stop.]" which makes no sense at all. You said any help would be appreciated and then dumped on the one and only person who tried to help you. You are on your own now.

The question was not answered / the question was... to find out how I could determine if indeed the problem was the gasket. It would make no sense to replace the gasket to find that it was something else & had to be removed again.