I get no spark between my plug and engine when turning ignition to "on" position, but I get spark when turning ignition from "on" position to "off" position. I replaced the ignition switch and still have the problem. Problem is consistent with both spark plugs.
-Joe

How old of a unit it is , a model #
Might help us , help you .

The model number is 917.258910.
I bought the tractor second hand about 4 years ago. The owner's manual has a rev. date of 3-31-97, so I'm guessing the tractor is a 1997 model year.