basicly what im sayin is, there is a reason it happened twice, wasnt afluke, ether your jetting is to lean, or your oil mix is to light, using cheap oil in a air cooled motor is a no no, its the motors life line,
soo many things can do it,simple as this, br8es or b8es plug, clean filter, clean carb, good oil, klotz, pro honda hp2 maxima, hell quick silver boat oil is good stuff for the price, PREMIUM fuel only, blasters dont need the octane of the fuel they need the burn quality to keep front detonating on a air cooled motor