BR9SH10 instead of BR8SH10's in a Yamaha 225 ?

[Tamale]

So I picked up a boat that has an 01 Yamaha EFI 225.

The plugs that are currently in it are BR9SH10 instead of BR8SH10 both NGK's. The manual says BR8SH10, so why would there be BR9's in there instead? The boat hauls [censored]. its a Skeeter ZX225, and has 27p prop. I hit 74 already with more to go, but the motor smokes alot and idles rough so I was gonna do a tune up. Should I put BR9's back in?

[Jason Hale]

The 8's are a hotter plug, look inside the cowling and it should have a sticker on it saying what plug goes in that motor, I think it calls for the 8's.