Special Interest Group

By Bill Salisbury.  This article originally appeared in "The Antique Outboarder" July 1991 Page 6.

Oil revisited! The discussion amongst members is an ongoing one and there seems to be as many opinions as there are members! I suppose my opinion is listened to by the members if only because I put it in these pages and most members read it. Personally, I don't think my opinion is any better than anybody else's, but the oils that I choose to use, might be!

There was a time when I was recommending the use of OMC's BIA oil in a ratio of 16:1 for the PO. I did use this for some period of time in my modified engine and it seemed to run well, however, I began to notice some spark plug fouling tendencies after extended idling periods. This seemed to become worse after the spark plugs aged. Each time this occurred, I noticed that the plugs would clean up if a long high speed run was made. The fouling was a black tar like substance forming on the plug.

My next step was to choose another oil, so I began with Castrol 2 Cycle Oil. This appeared to be like the outboard oils of the past, not BIA certified. This oil, mixed at the same ratio, worked very well and had none of the black goo fouling tendencies. At last, the problem was solved, once and for all. Wrong! There was really no problem with the oil except for the fact that I couldn't get it any more. I know that it is still available, but the local stores probably carry it only in the winter when no one needs it.

Last Spring while at the Mt. Dora boat show, several members talked about the possibility of using aviation oil which is available at nearly all airports. Steve Wood mentioned that he had been using it in all of his engines for some time and had fine results. I know that Mike Hodes has been using it in his Big Four and PO, having very good results. I, too, have been using it all this past summer and with good results. No ring sticking, no fouling after extend­ed idling. I am using it in both my PO and 460 at 16:1 ratio.

What do you ask for when you go out to your local grass field airport? Ask for Aero-Shell pure mineral oil (no detergent in it) and it comes in 30, 40, 50, and 60 weight. I have been us­ing the 40 weight. Do not be confused by the number on the plastic bottle. It will say, in the case of 40 weight, 80 grade. This is a military rating system, still used in aviation. If you want 50 weight, ask for 50 weight, but it will say 100 grade on the bottle. They will know what you mean. Cost? About $1.75 to $2.00 per quart. Now, this should give the members more to talk about when the subject of oil comes up!


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