Spark Plug Indexing?

[Capn_Hookem]

Can someone explain the plug indexing process for a 1997 150 HP Oceanrunner? I keep reading that it needs to be done but I'm unsure about why and don't know the procedure for this engine. (Moddel is 150EXEU)

 

[Walker]

Re: Spark Plug Indexing?

Doesn't need to be done on your motor.
The Ficht motors needed it, but not yours.

 

[steelespike]

Re: Spark Plug Indexing?

I did a little quick research.I don't think indexing "needs" to be done on any engine.The idea is to aim the plug gap in exactly the right position for best performance.The position varies depending on the engine.Results also vary with a 1% increase about the most that can be expected.On your 150 that's about 1.5 hp.On motors with surface gap plugs it would seem indexing would not be needed.