I have a Briggs motor 126T02-0675-B3 that starts easily and runs well for several minutes but begins to run unevenly, spits droplets of gas out of the carb, and may die after warming up. This appears to be an electrical problem because the only clue I have found is that this happens consistently with the specified resistor plug installed but it runs noticeably better with the equivalent non-resistor plug. I have a fair amount of experience with small engines and have addressed such things as carburetor, valve condition and clearance, ignition coil, kill switch and wire, high voltage lead to plug, cleanliness of gas tank, venting of the gas tank cap and condition of the flywheel key. I have also tried to evaluate the strength of the magnets in the flywheel and they appear to be OK. I am apparently missing something relatively obscure that I haven't encountered before. I would appreciate any suggestions of anything else I should check.