Champion J6J is the recommended plug which has been changed to J6C by Champion.
The recommended plug gap for the 2000 model, 4 hp Johnson is .030 in.
The proper spark plug for 4hp Briggs & Stratton is a J8 which I use in all my motors.
what spark plug do i need for a 3.75
Mine is a 2000 model and it has an NGK R BPR7HS10
Johnson 4hp outboard bj4brcud
The original spark plug fitted was a Champion 8 com but these are very scarce these days ,Champion D16 is an equivlent or NGK make an 18mm plug that is also suitable
The 4WF69B model, 4hp Johnson, would be a 1969 year model.
Jew
Far easier to drain old oil through filler tube, remember to always keep cylinder head [spark plug end] pointing up when tipping mower.
b 08800420
1969.
1969