Next time you finish with the generator, turn the fuel off and let the engine starve
Modern plugs are not glazed because of the lead that comes out of the glaze
( you can still buy high lead table wear that will cause you to injest lead but no one worries about that )
If the plug is not hot enough, the unburned fuel deposits on the insulator so when you go to start the generator , the spark tracks down the side of the insulator in place of jumping the gap , so the old "wet plug syndrome" but the plug does not look wet .
If that works then either go 1 plug hotter or just keep on starving the engine off .
You will probably find that if you put your "eaten" plug into a hot engine it will work fine .
But don't worry too much because the new Californian battery powered generators will be out shortly
