A push mower won't start without the blade attached.
A riding mower won't start without someone sitting on it.
If a carburetor primer bulb is problematic to
start, lean the mower a few inches left, right,
straight back, whichever works. Lean it for a
few seconds, then, try and start the mower.
There's no smoking when working on mowers, especially indoors!
If you must smoke, leave the mower and smoke outside.
Short hair, no loose clothing. Strings hanging from
coats and necklaces could kill you.