I think this is all getting a bit personal!
A quote from Tue who should know his stuff,
Originally Posted by tue
We only use NGK's at work unless its a Johnson/evinrude. They seem very keen to only run best on Champions?? Some plugs that Champion do and Johnson/evinrude recommened don't have an NGK equivilant
So it is not only Mr Cod who is saying that some engines like certain plugs!
I have a Johnson which likes Champions, I had it serviced last year & the mechanic said they where just fine & did not knead changing! I changed them this year but kept the old ones as they looked all OK so now I have a set of spars that I know work!