Hi Gadge,
That seems like it could be the problem and then as soon as I pull out an NGK plug it always puts doubts in my head. It is the correct plug for the motor. I have never really studied plugs to the point of the heat range numbers on the plug and how they rate the numbers between different brands. This plug is a BKR5E and the Champion is a XC12YC so do you think the Champion might be a hotter plug going by the numbers? As for it being a faulty plug apparently this plug was recently replaced for the same reason, so I am expecting it to come back with the same problem shortly. This could also be an ongoing NGK problem so the next thing is to change brands and see how that performs
