Which spark plug to use b93 50hp Evinrude

[blink3477]

"My manual says QL78C and the

"My manual says QL78C and the Champion chart says QL78YC.

What does the "Y" stand for? I've run them both and don't notice a difference.

Also, my manual states that I should use QL16V surface gap plug if operated at sustained high speed.

Since this is a jet outboard and I drive it like I stole it, should I be running these instead?

Thanks."

 

[haffiman37]

"The YC plug has an extended c

"The YC plug has an extended center electrode that gives an improved idle.
In Your case,(newly stolen), try the QL16V plug."