Cooling System Components; Water Pump And Intakes; Exhaust Housing; Pressure Relief Valve - Evinrude E-TEC E40DRLSCB Service Manual

COMPONENTS

Water Pump and Intakes

External water intakes mounted in the gearcase
housing collect water and must supply the inlet
side of the water pump with an unrestricted and
unaerated water supply. Water is drawn into the
water pump through a hole in the lower plate of
the water pump assembly. All cooling water to the
powerhead is provided by the water pump.
•
A nylon wedge (impeller key) is used to engage
the impeller bushing and driveshaft.
•
The nylon impeller housing with liner must seal
against a separate water pump plate.
•
The bottom plate MUST seal to gearcase.
•
The pump operates as a positive displacement
pump at LOW speeds (below 1500 RPM) and
as a centrifugal pump at HIGHER speeds.
Refer to WATER PUMP SERVICE on p. 278 for
servicing.
2
4
1
1. Water inlet
2. Water outlet
3. Seal
4. Plate
IMPORTANT:
a small hole to the rear of the water outlet. This
hole provides cooling water for the tip of the
exhaust passage. Be sure to use the correct parts
when replacing the water pump.
1. Hole

Exhaust Housing

The water pump outlet connects with passages
located in the outboard's midsection. A grommet
seals the water pump housing to the exhaust
housing.
Water supplied to the exhaust housing provides all
cooling water to the cylinder block.
3

Pressure Relief Valve

A pressure relief valve is used to control water
flow and operating temperature at higher speeds
(above approximately 1800 RPM). The pressure
relief valve opens as water pressure increases.
Spring tension sets the opening pressure.
Overheating: A restricted or faulty valve typically
results in HIGH SPEED overheating.
001216
001217
COOLING SYSTEM
COMPONENTS
The water pump housing includes
1
004970
10
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