The 1984 Johnson 9.9 original owner's manual specifications call for a Champion L77J4 spark plug with a gap of 0.040" (1.0 mm). Have there been any changes in either the recommended plug or gap? Thanks for your help.
- Status
Outboard Plugs
Bob That looks just right. Also be aware that there are other plugs you can use. Champion, NGK, etc. All stores will have conversion charts from manufacturer to manufacturer to swap plugs. I've used the L77J4 as well as the NGK replacements in our 9.9 Evinrude for years with no change in performance. All have the same gap. My only "trick" is to put new plugs in at the bginning of every season regardless of how little I may have used the previous plugs. Sure makes starting easier on the arm! Stu
Bob That looks just right. Also be aware that there are other plugs you can use. Champion, NGK, etc. All stores will have conversion charts from manufacturer to manufacturer to swap plugs. I've used the L77J4 as well as the NGK replacements in our 9.9 Evinrude for years with no change in performance. All have the same gap. My only "trick" is to put new plugs in at the bginning of every season regardless of how little I may have used the previous plugs. Sure makes starting easier on the arm! Stu
- Status