Well, I changed the blade. I still have both hands and feet, and my head. All parts accounted for (mine and the lawn mower's). I didn't cut myself on the blade, but I did manage to slash my finger a bit on the damn bubble pack plastic package the blade came in.

(Is there an anarchist group I can join that is devoted to the anahilation off bubble pack packaging? I hate that. )
But I have to take it apart again, I guess. Something's wrong with the self propulsion. I thought it was that there was something wrapped around the crank shaft, and there was twine or something that got up under the debris cover, too, but I cleared that all out and its still not "self propelling". I guess I should have put a new drive belt on while I was at it, too. Ah well.
At least its cutting grass without the blade digging into the ground.
And having been initiated into the scary world of "under neath the lawn mower" I've got my own hint to give.
If you are going to drain the gas and oil from a lawn mower in order to tip it over to work on the underside: When you get it all done and turned back upright and put back together, all the bolts tightened, all the screws screwed, and are ready to start it up to try it out.....put a LITTLE BIT of oil in it and about a quarter cup of gas. Just enough to start it and run it for about thirty seconds. Then, try it out BEFORE topping off the oil and gas. Just in case you find you need to tip it over again to adjust or fix something else, so you don't have to drain a full tank of gas, and a full engine of oil. Guess who didn't think of that?

