Thermostats; Block Venting; Operation; Cylinder Block / Cylinder Head Cooling - BRP E250DHLSCS Service Manual

COOLING SYSTEM

OPERATION

Overcooling: Debris may prevent the valve from
closing completely.
Pressure Relief Valve Components

Thermostats

Thermostats control water flow and operating
temperature at lower speeds (below 1800 RPM).
Overheating: A restricted or faulty thermostat typ-
ically results in LOW SPEED overheating.
Overcooling: Debris may prevent the thermostat
from closing completely.
Thermostat

Block Venting

A fitting and hose from the top of the block allows
the constant movement of water and/or air from
the block. Circulated water flows through the EMM
and Vapor Separator before exiting through the
overboard indicator.
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OPERATION
All models use a two-stage cooling system
design. The cooling system is dependent on water
pump pressure and controlled by thermostat and
pressure valve operation.
IMPORTANT:
flow through the outboard reduces cooling system
performance and may lead to severe powerhead
damage.
DRC8113
Cylinder Block / Cylinder Head
Cooling
The flow of water through the cylinder block and
cylinder heads is controlled by two thermostats
and one external pressure valve. The pressure
valve is connected by hoses to the top of each cyl-
inder head.
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1. Thermostats
DSC02335
2. Pressure valve assembly
The thermostats and pressure valve control the
flow of water entering the vertical water passages
of the cylinder heads.
At low speed, the pressure valve is against the
seat and the thermostats are closed. Warm water
from the cylinder block gradually migrates to the
thermostat pocket at the top of each cylinder
head.
The thermostat opens when the water tempera-
ture reaches approximately 143°F (62°C).
Restricted or inadequate water
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