'83 Evinrude Fuel/Oil Mixture Problem

[big dan]

I'm currently running a 140HP V4, 1983 Evinrude outboard. My problem is that I'm fouling out the spark plugs. I need to know what my fuel/oil mixture should be. Right now I'm mixing 6 gal of gas with 16 oz of oil, or a 48/1 mixture. The plugs still continue to have a lot of oil residue on them. The spark plugs are NGK #5526-BUHXW-1. The original plugs being used at the time of purchase were Champion QL77JC4. I'm thinking that maybe if the oil mixture is right, then I may not be burning a hot enough plug in there. Thanks for the help.

 

[DJ]

Re: '83 Evinrude Fuel/Oil Mixture Problem

big dan,<br /><br />Your ratio is correct (one pint-6 gallons 87 octane fuel) You don't need premium.<br /><br />The correct plug is a L77JC4. I believe those are the same as QL77JC4. I don't like anything in OMC's but Champions. Tried them all, the Champ's. work best.<br /><br />Your fouling could be from two reasons.<br /><br />1. Your carburetors are in need of attention and are running rich-float, needle valves.<br /><br />2. Your thermostats are stuck open, thus the engine never reaches proper operating temp.<br /><br />DO NOT go to a hotter plug. THat can be disastrous for your piston tops.

 

[big dan]

Re: '83 Evinrude Fuel/Oil Mixture Problem

Now that you mention it I have noticed that the temperature guage never quite changes while the outboard is in use. What is the optimal or normal temp my motor should be at while operating?

 

[OBJ]

Re: '83 Evinrude Fuel/Oil Mixture Problem

Hi BigDan....<br /><br />Most of the OMC engines run a 140 degree tstat. At idle, the temp on the flat area right behind the head should run between 140 & 145 degrees. Flat out WOT, the temp will rise some. Don't know what yer temp gage says, but you want to get some idea of what temp it's reading at idle and compare that with WOT operation. Anything else would mean something is amiss.