no ground on my plugs

[sheaston]

i'm new to boating, and i just got new spark plugs for mu 50 hp force and there are isnt a ground on my plugs (just flat on the bottom) how will this make spark? with nothing for it to jump across.

 

[Paul Moir]

Re: no ground on my plugs

That's what they're supposed to look like. They're called 'Surface Gap' plugs, and the spark jumps from the center electrode to the shell.

 

[sheaston]

Re: no ground on my plugs

Thanks