The key replaced, it still doesn't start! Arrrgh! It has spark &
won't start even with gas squirted in the cylinder.

The sheared key is a common B&S problem when the ignition timing is off.

Have you checked the points gap?

Also, you said "it has spark". Is that _at_the_plug_, or just from the
wire to the block? (hint-- wet plugs often won't spark).

Since (DAMHIKT) the points gap can shear a key, I'd be looking at that.

If they're too open, they'll be advanced. That can be caused by mis-
adjustment, but also by wear (burning).

LLoyd