For a 1971 Johnson 25 hp outboard motor, the recommended spark plug is the Champion J6C or an equivalent, such as the NGK B6HS. Ensure that the spark plug gap is set to the correct specification, typically around 0.030 inches. Always refer to the owner's manual for specific recommendations and maintenance practices.
The 25 hp Johnson outboard runs a plug gap of .030 in.
champion j4c
advance auto sells a spark plug tester for around 25 dollars
The required plug gap for a 25 hp Johnson outboard is .030 in.
Spark Plug gap is .025
0.85
The correct spark plug gap for the 1994 model, 25 hp Evinrude outboard is .030 in.
its gaped at .25
.25
25-.30
According to weedeater.com they are all to be .25..
25 thousands of an inch