mowers use a much different plug than the sprint needs. a mower uses a j19lm or an rc12tc, or an n11yc. these plugs are no where near the correct heat range. they wont get any better spark. spark is the same on every plug unless it is a resistor type plug. lawn mower plugsare too short. the way a spark plug works is similar to a glow plug. the ceramic core reaches a specified temperature. the sark gets the fuel burning, and the red hot ceramic finishes the burn. using the wrong plug can cause a lot of engine failures and problems such as overheating.