indexing plugs ?

[DUP1014]

This might be a dumb question .But what is the reason for indexing a spark plug?
I am going to change plugs soon in my Johnson 150 Fast strike j150 gleue 97 model.also how often shoud you change the plugs?

Thanks Brian

[SEAHORSE]

Only the FICHT and E-TEC engines need to have the plugs indexed, which means the open end of the spark gap has to be facing or within 90° of either side of the fuel injector for best combustion.

Your engine does not need the procedure.

Change your plugs every 100 hours as that is the same interval that your engine needs complete servicing, or once a year whichever comes first. Use Champion QL78YC plugs gapped to .030"