I would not put Bosch plugs in a lawnmower,let alone anything else.I use NGK in every motor I touch.Including my generator which ate the OE Champion in 2 weekends use,the NGK has done 2 seasons now with the ocasional clean as its 2 stoke..
I agree John. I can't say I have ever had a bad spark plug. The rest of the ignition system is MUCH more important. The spark plug just has to make a spark. Physics and Chemisty do the rest.