[OMC-Boats] Engine Fuel Octane Recommendations

Awhile back we were discussing OMC's factory recommendation on
gasoline octane ratings, in light of engines built prior to 1973-74
were not designed with hardened valve seats for no-lead gasoline.

The confusion stems from the fact that in the 1960's OMC owners
manuals the referenced octane ratings used the older "Research method,
aka RON."

OMC issued a 1974 clarification that their 4-stroke engines built
before 1972 require gasoline with a posted pump octane rating, (aka as
PON) of not less than 89. (That translates to a mid-range or higher
quality REGULAR in most parts of the US. REGULAR is 85 - 87 in most
areas of the US, while premium is usually 91 - 93 PON.

Note: In the US PON is determined or = (R+M)/2 .

For more info on see: http://en.wikipedia.org/wiki/Octane_rating

The Bottom line: Don't worry about lead additives or exclusive use of
high octane fuel (or additives). Do filter your fuel religiously and
use a good-to-medium blend of pump available fuels.

Lee
Received on Sunday, 12 July 2009