The following spark plugs are specified for a 1990-1999 Yamaha RT-100: NGK B7ES (or if you want to upgrade to iridium, BR7EIX) Denso W22ES-U (for the iridium version, IW22) FYI, the spark plug gap is .022"
I was looking at fordparts.com and it shows ( .044 inch ) for all the factory available engine sizes in a 1975 Ford F-100
The correct spark plug gap for the 1979 model, 100 hp Johnson outboard is .030 in.
.040
18436572
0.40
it uses a RDJ7Y
Spark plugs don't really burn out, they foul out. A spark plug is used to ignite the fuel/air mixture squirted into the cylinder by the fuel injector. The plug sends a spark and boom small explosion. However gasoline is not 100% clean, so it leaves carbon deposits on the plug. Over time these deposits foul the plug.
The correct gap is .035 of an inch.
On the 1999 Honda 100 Ace the Plug Gap is suppose to be .36 thousands
0.35 th
According to one of the Ford websites : For a ( 1960 ) F-100 , 3.6 liter / 223 cubic inch six cylinder engine : ( .035 inch spark plug gap )