Small Engines (Lawn Mowers, etc.): craftsman lawn mower 6hp front wheel drive rear catcher

Question
what type and size spark plug does this lawn mower take

Answer
How old is the mower and what is the model number?  You will find the mower model number on a sticker, about the size of a business card usually located on the rear of the mower.

The model number format will be 917.xxxxxxx

Send me the model number so I can look up your mower.
Eric