Sounds to me like you have a thrown rod and its jamming up the engine. Take the spark plug out, tie down the break lever and see if you can turn the blade over by hand both ways. If your blade turns over freely and you can hear something knocking around then bad luck your motor is blow.

I tried to go underneath, I mean, it turns both ways, you kind of have to force it a bit though...the thing on TOP turns too, I don't hear anything "Knocking" though.

I'm wondering if the flywheel brake is broken.
That would cause it to die and be difficult to pull start.

I have no idea what engine make or model it is you have but most are similar. Follow the cable that runs from the handle bar to the engine shroud. Remove the shroud and check the cable connection at the brake. Maybe the cable is broken there or came loose somehow.
Its not that difficult, you may need allen style wrenches or regular screwdrivers to do.

Give it a whirl, what have you got to loose?
Neal

It doesn't have a brake, it's a push mower. (not self propelled.

How old is it?

I guess a couple of years. Got it from a neighbor of mine. It looks new..it's not an OLD push mower.

Then it has a safety device called a flywheel brake.
Its purpose is to shut the engine down and stop the blade when the operator releases the "bail". The bar thing under the handle bar you hold onto when you start and use the push mower.

This mower should have one, if not you're machine has been modified or is older than 1984.

When the cable on these fails or breaks it will cause the brake to engage the flywheel at full force causing you to not be able to pull the rope very easily and it most certainly will not start because it also cuts the circut to the spark plug.

But hell I don't know you never really gave much of a clue otherwise so I'm done.
Good luck, Neal

Hm, interesting...if that's the case...what kind of repairs are required?

Somoene was telling me it was because the oil was past due on changing, but I don't think it would keep the chord "Locked" and un-pull-able.

If your mower engine has a dip-stick (the thing that comes out when you check the oil, you may have added too much oil! If you filled up to the top of that hole, thats too much oil, and will give the problem you have now! (don't laugh, i've had a case like that)!
Another problem: When you let the rewind starter cord pull back into the housing, it may not have gone back in correctly, and jammed itself in the housing! This would cause the engine to be hard to turn by hand.
And, any time you have to tip the engine up, do not tip it up with the carburetor on the down side! Always do it with the muffler side down, or with the front of the mower up! This keeps engine oil where it belongs,but it will clog the carb, if done wrongly!

Well, what did you find? A little news about any success from our tips would be nice! We're left hanging out here, wondering!
By: Rustyj14