Incorrect Spark Plug? - Evinrude Starflite 100hp 1972 - 100293R

Hi All,

I purchase an 1972 evinrude starflite 100hp (model 100293R) a couple of years ago and have been using NGK B9HS spark plugs in it as that was what was originally installed in it when I bought it. I checked the manual and it calls for a Champion L77V which apparently converts to an NGK BUHW. Does anybody own the same model and if so, what spark plug are you using in it? Not sure if it would make any difference but my motor was converted to ignition coil instead of power pack. Would that have been a reason to use a different plug or have they just used the wrong one. It seems to run fine except it does load up on idle and floods itself occasionally. Not sure if this is spark plug related though but thought it worth mentioning.

Any advice would be greatly appreciated.

Thanks. Amon.

Re: Incorrect Spark Plug? - Evinrude Starflite 100hp 1972 - 100293R

Champion L77V and NGK BUHW are both surface gap plugs.....if you use your boat for sustained high speed use they will be okay. For general allround use you are better off fitting Champion QL77JC4's......

http://continuouswave.com/whaler/reference/BRP_SparkPlugChart2007.pdf

Re: Incorrect Spark Plug? - Evinrude Starflite 100hp 1972 - 100293R

Surface gap plugs such as the Champion L77V and NGK BUHW run continuously fouled at low speeds, but the high-voltage CD ignition will fire the plug due to its power and quick "rise-time" to generate the voltage needed to overcome fouling. You say your motor was converted to a regular coil ignition so it will need standard type sparkplugs such as the QL77JC4.

Check your high speed timing setting as a regular ignition is less powerful and is slower to develop enough juice to spark the plug.