How can I fix my Craftman LawnTractor Model #917.270780?

Check the top of the transaxle. On mine I have to remove one of the back tires to get to the transaxle fill plug.
As for the sparkplug setting -- it depends on the type of engine you have -- either a Briggs-Stratton or Kolher. You have to also consider the horsepower, Any or all of the above may change the gap setting.

J Choate
November 2007