A boat named pickles! In this video a full service is conducted on a Yamaha T8. Lower end oil change, impeller, oil change, spark plugs, fuel filter, and carburetor cleaning. Unfortunately my camera during the cleaning however I'll some links and parts below.

Spark gap; .09 - 1mm or .035 - .039 in.
https://outboards.yamaha-owners-manua...
Page 47

Carburetor cleaning vid;
   • 15 minute Carburetor Cleaning Rebuild...  

Parts used;
Spark plug BR6HS-10 (x2)
Impeller 63V 44352-01
O-rings 90430-08003
Fuel filter 68T-24251-01-00
10-w-30 mineral base oil (800ml)
Carburetor Cleaner
Marine Grease

Any questions just ask.