Sorry just a little rant there. Ferm, I see why you got away from the car biz. I too work with jackknobs that can't even replace a spark plug, let alone know anything about engine performance.
So no regular NGKs either?

In a EVINRUDE or JOHNSON with carbs run only the CHAMPION plugs. The QL77JC4 work for almost all of there engines, and are the best all round plug. NGK's are known to make an OMC run like CRAP! Even some of the older MERCS run better on the CHAMPIONS than NGK's. But on the other hand, I've put CHAMPIONS in YAMAHAS and SUZUKIS and had them give off horrible radio interference.