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