[BruceAML]

I have a 1962 model 50931A Evinrude Starflite IV 75 hp. I have the original parts manual and owner's manual which lists a Champion J4J which has been replaced by a Champion J4C. Does anyone know of any OMC service bulletin that specifes a different spark plug? The original oil mixture for this engine was 24:1 and I wonder if a 50:1 mixture would work better with a different spark plug.

[rickdb1boat]

Hi Bruce

The J4C is the correct plug gapped at .030. 24:1 is the mix required for that year due to bronze bearings. 40:1 would be safe though according to some....

boatsetup.com/SparkPlugChart.pdf

http://forums.iboats.com/bbBoard.cgi?a=viewthread;fid=36;gtid=1035556 ] Click Here [/url]

[F_R]

I don't think there are any bronze bearings in that motor. I know what I would do, 50:1. But if you do and it blows up, don't come blaming me. It was ready to blow anyway. It's your choice.

[Bru45]

I just was given a 62 50931-A,but I have a 68 100hp and I was wondering if you might know if the gear reduction starter will fit my 68?.
The 75 was working before it was stored and is still very tight,lower unit is soild.I'll see what plugs are in it and post it

[JB]

Please don't hijack old threads, Bru. Start a thread of your own with your question.