After Filling the gas tank on my Sears Craftsman lawnmower 917.383242 to any level above approximately 1/8th of the tank the gas begins to leak out of the air filter. It seems to take about five to ten minutes before starting to leak. It is especially so when the throttle is left open to the highest level/starting position. When the lever is flipped back to the lowest rpm's it abates for maybe ten minutes before leaking again. Eventually the air filter becomes saturated with gas. The mower seems to run properly in spite of the gas leak. Presently due to the problem I run the mower in short runs with the tank filled to the 1/8th level.

Garden - Craftsman