The Tecumseh Enduro 16hp engine typically uses a spark plug with the designation "Champion RJ19LM" or an equivalent. It's important to verify the specific model and year of your engine, as variations may exist. Always refer to the engine's manual for the correct part number to ensure optimal performance.
According to my owners manuel the spark plug gap is 30
Tecumseh Part #611049 - Champion Spark Plug #RCJ8Y
Tecumseh website, "All spark plugs air gap is .030."
My book for my John Deere snowblower , which has a 5 horsepower Tecumseh engine , shows to use the Champion RJ17LM spark plug
The plug gap for a 5.5 hp Tecumseh is .030 in.
.30
.030
Chanpion RJ19LM
Champion RN4C
An Autolite 258 is the recommended spark plug for a 6. 5 horsepower Tecumseh engine. A Champion RJ19LM also is recommended by the manufacturer.
rj8 is used for a 7hp Tecumseh that powers a 22" yardman snowthrower
Champion J8C