Ya gotta put it on the pins or it'll fly all over the place. That's just the way it's made.

I took a chance and put the new blade on and cranked er up. VERY little vibration, Put it 2' onto the lawn and the clacking was scarey. Got an idea to buy a mower with a 4.5 B&Stratton like I have now and see if I can swap motors. If not, the new one will have to do... a lot cheaper... manual height adjustment and the side discharge chute is bolted solid NOT a good thing in heavy grass). But, that is my only option. The perfect mower was on sale at Home 'o The Hardware Man on the the front page of today's flyer and I was there at opening... oops, sorry, the supplier could not deliver and we can't get any until next spring. Grrrrrrrrrrrrrrr.