Outdoor Power Equipment and Small Engines - Honda Quad Blade will not start?

I was bagging and stopped the mower to dump the grass, came back and it will not start. I have checked the fuel line and float, checked the sparkplug and replaced, cleaned the carb, drained the fuel put fresh. When I pull it a little puff of white smoke comes out. It has always started first pull.

I don't know what a Quad Blade mower is, so, is it a riding mower or a walk-behind? It will be helpful to those of us that don't know such to post the model and serial and type numbers of the chassis as well as those of the engine. Initially though, I'd ask if you checked for spark at the spark plug before you installed the new one? If so, what was the result? Secondly, and based on the white smoke, this could indicate that you have fuel in the crankcase. Does the oil smell of gasoline? If so then you'll need to remove, soak and recondition the carburetor.