Engine Oil Recommendations-Race (R) Models; Checking And Adding Engine Oil - Mercury 300R HD CMS Mechanical Operation And Maintenance Manual

The fuel demand valve has a manual release. The manual release can be used
(pushed in) to open (bypass) the valve in case of a fuel blockage in the valve.
a
Engine Oil Recommendations—Race (R) Models
Mercury or Quicksilver NMMA FC‑W or NMMA FC‑W catalyst compatible
certified SAE 10W‑30 Marine 4‑Stroke Engine Oil is recommended for general
all‑temperature use. As an optional choice, Mercury or Quicksilver SAE
25W‑40 Mineral Marine 4‑Stroke Engine Oil or SAE 25W‑40 Synthetic Blend
Marine 4‑Stroke engine oil may be used. If the recommended Mercury or
Quicksilver NMMA FC‑W certified oils are not available, a major outboard
manufacturer's brand of NMMA FC‑W certified 4‑Stroke outboard oil of similar
viscosity may be used.
IMPORTANT: The use of nondetergent oils, multiviscosity oils (other than
Mercury or Quicksilver NMMA FC‑W certified oil or a major brand NMMA FC‑W
certified oil), full synthetic oils, low quality oils, or oils that contain solid additives
are not recommended.

Checking and Adding Engine Oil

IMPORTANT: Inspect oil for signs of contamination. Oil contaminated with
water will have a milky color to it; oil contaminated with fuel will have a strong
fuel smell. If contaminated oil is noticed, have the engine checked by your
dealer.
FUEL AND OIL
b
a -
b -
c
c -
46453
Engine Oil
+120
+100
+80
+60
+40
+20
F
6.6 L (7.0 U.S. qt)
24
Fuel demand valve ‑ installed in the
fuel hose between the fuel tank and
the engine
Manual release
Vent/water drain holes
+49
+38
+27
+16
+4
-7
-18
0
C
64064
eng