OK all you mad scientist / mechanics heres my dilema. My little Honda walk behind will be running fine, I stop and fill it with gas from the same can it was running fine from and it won't start. It only happens on this property which happens to be a medical clinic with a MRI Trailer with giant magnets which we mow next to for about 10 minutes. What is this doing to my mower. It will sputter and barely idle, then die. Every week in the same spot. Now today it quit won't run at all or only sputters and dies. I've changed spark plugs and drained the fuel bowl no help. Did the magnetic field hurt the magneto? Any suggestions?