Specifications

73
CB66
Seawater Pump Impeller
This maintenance should be performed by an Authorized MerCruiser Dealer.
1 Seawater pump impeller should be inspected whenever insufficient seawater flow is suspected (if operating
temperature exceeds normal range).
CD625
Fuel System
CAUTION
Absolute cleanliness is required for work on the fuel system, fuel injection components have very
close tolerances. Even minute particles of dirt or small amounts of water can impair the function of the
fuel injection system.
FUEL TANK CLEANING AND FLUSHING
IMPORTANT: Diesel fuel should not be left in tank during winter storage, as an accumulation of rust,
sludge and wax residue will form.
2 Refer to boat manufacturer’s instructions and clean fuel tank at specified intervals. Unless specified other-
wise, flush and clean diesel fuel tank every 1000 hours, maximum.
CD283
HAND PUMP/PRIMER
3 A plunger-type of hand pump/primer is located on the fuel filter bracket and is used to: (1) refill fuel system
if system was run dry; (2) refill fuel filter when changing filter; or (3) to prime the fuel system if engine has not
been run for a while.
To operate the hand pump/primer, move the plunger (upper portion) up and down as needed.
CE63
PRIMING FUEL SYSTEM
Prime engine if it has not been run for a while or if engine will not start. Move the hand pump/primer plunger up
and down several times as previously outlined. Attempt to start engine.
CD284
FILLING FUEL FILTER
NOTE: Follow this procedure after installing new filter or if fuel has been drained from filter checking for water.
4 Loosen bleed screw on fuel filter bracket. As previously outlined, move plunger on hand pump/primer up and
down repeatedly, until an air free stream of fuel flows from bleed screw. Filter is full when this occurs. Tighten
bleed screw.
CD578
DRAINING WATER SEPARATING FUEL FILTER
WARNING
Be careful when draining water separating fuel filter. Diesel fuel is flammable. Be sure ignition key is
OFF. Do not allow fuel to contact any hot surfaces which may cause it to ignite. Do not allow sources
of open flame in the area. Wipe up any spilled fuel immediately. Dispose of fuel soaked rags, paper,
etc. in an appropriate air tight, fire retardant container. Fuel soaked items may spontaneously ignite
and result in a fire hazard which could cause serious bodily injury or death.
IMPORTANT: Keep diesel fuel away from drive belts and other engine components that could be harmed
from being exposed to, or saturated with, diesel fuel.
5 The filter can be drained of water and small dirt particles by opening drain cock at bottom of filter. Open by
turning the drain counterclockwise
(as viewed from the bottom of the filter) . Drain until fuel is clear in appearance.
Close drain by turning clockwise. Tighten securely. Fill fuel filter as previously outlined.
NOTE: To ensure complete draining, in warm weather open the water bleed valve before starting daily opera-
tions. In cold weather, where there is a possibility that the condensed water will freeze, drain the filter shortly after
the end of daily operations.