Crankcase Oil - Mercury 350 Mag MPI Manual

Because of possible adverse effects of alcohol in gasoline, it is recommended that only alcohol-free gasoline
be used where possible. If only fuel containing alcohol is available, or if the presence of alcohol is unknown, in-
creased inspection frequency for leaks and abnormalities is required.
IMPORTANT: When operating a MerCruiser engine on gasoline containing alcohol, storage of gasoline
in the fuel tank for long periods should be avoided. Long periods of storage, common to boats, create
unique problems. In cars alcohol-blend fuels normally are consumed before they can absorb enough
moisture to cause trouble, but boats often sit idle long enough for phase separation to take place. In
addition, internal corrosion may take place during storage if alcohol has washed protective oil films from
internal components.
CA693
To help obtain optimum engine performance and to provide maximum protection, we strongly recommend the
use of Quicksilver 4-Cycle 25W-40 Marine Engine Oil. This oil is a special blend of 25-weight and 40-weight oils
for marine engines. If not available, a good grade, straight weight, detergent automotive oil of correct viscosity,
with an API classification of SH, CF/CF-2, may be used.
In those areas where Quicksilver 4-Cycle 25W-40 Marine Engine Oil or a recommended straight weight oil are
not available, a multi-viscosity 20W-40 or, as a second but less preferable choice, 20W-50, with API service rat-
ings of SH, CF/CF-2 may be used.
IMPORTANT: The use of non-detergent oils, multi-viscosity oils (other than Quicksilver 25W-40 or a
good quality 20W-40 or 20W-50), synthetic oils, low quality oils or oils that contain solid additives are
specifically not recommended.
The chart below is a guide to crankcase oil selection. The oil filter should always be changed when changing
engine oil.
36

Crankcase Oil

Quicksilver 4-Cycle 25W-40 Marine Engine Oil
SAE 30W
SAE 20W
°
32 F
°
0 C
AIR TEMPERATURE
SAE 40W
°
50 F
°
10 C
75796