It is pretty hard to start a mower without a blade.
If you took the blade off take a straight edge against the crankshaft to see if it is bent. If it looks straight then replace the blade.
Make sure you remove the spark plug wire. Crankshaft not drive shaft.

I'm sure the crank is bent. I turn the mower up with the gas tank almost empty and the carb in the up position. Remove the spark plug and tie the bail fast to the handlebars to release the engine brake.

Now you can rotate the blade. If both bottom edges of the blade are in line with a point on the deck, your blade is good. It can vary up to a half inch or so. You'll also see if the crank is bent.

I've heard stories that once the high point is determined in the shaft, a small sledge hammer can be applied to the crank stub to knock it towards the center. Re-try and look for a high spot and use the sledge again. Of course, I've only heard of this happening from old timers and never done it. If the crank is bent, you might consider a new mower.