Have an older Craftsman 18HP B&S, 42" cut, riding lawn mower. Will not start. Has fuel, install two (2) new spark plugs, has oil, engine turns over but will not start. Last used 2wks. Ago. Any suggestions?

Hi,
An older machine is probably an opposed twin. There is a yellow or white wire that is on the right side of the air filter box. Unplug it and try again; this separates the engine from the rest of the
Machine(as far as cutting it off) and will tell you if you need to replace the armature. If it still does not start, it is probably the armature.
If it does, then you have to figure out what prevents it(the key switch is where you start.)
Peace,
Clarke