[steam_mill]

Just finished breaking in my new motor and would like to change the plugs.I'm quoted both from the NGK site and Merc site for spark plug BUZHW-2.There is no electrode! Therefore no gap.Is this correct?How does a non electrode spark plug work?My old '72 Evinrude 50 also had non-electrode spark plugs. But I never used them since the part number now quoted with electrode.How does a spark plug without electrode work?Where does it ground?

[andrewkafp]

It does have an electrode. The spark jumps from the centre over to anywhere around the outer ring.The advantage is, if part of the ring gets oiled or dirty, it will default to another part. This creates less wear , and no need to set the gap.If these are the plugs,specified by your manual. Don't use other types. They are the correct heat range and are specifically designed to be used with your motor.

[Bob Kimber]

steam_mill,The plug you have been quoted is the correct plug for your engine. In Australia Mercury marine advises NGK BUHW-2 for this engine and the 75hp 3cyl. I'm not sure of NGK specification but the plug specified for the US and Canada is probably a resistor type to reduce interference in your electronics - (radar, gps etc)Bob

[andrewkafp]

Hey BobHow's Sunny Nth Qld (My home away from home) ?