Operation; Water Cooling System - BRP Johnson 4HP Service Manual

POWERHEAD

OPERATION

OPERATION

Water Cooling System

The water cooling system includes the gearcase water pump, the water supply tube, the powerhead
water passages and the thermostat.
This system cools both the powerhead and exhaust and is shown in schematic from below.
If overheating occurs, the components of the cooling system must be inspected for blockage, corrosion
build-up or component damage.
[Component inspection]
Water pump / Impeller ............................................ 8-8
Water tube .............................................................. 7-10
Thermostat.............................................................. 6-31
Cylinder head ......................................................... 6-12
Cylinder block ......................................................... 6-21
CYLINDER
BLOCK
CRANKCASE
DRIVESHAFT
HOUSING
EXHAUST OUTLET
6-40
[Refer to page]
CYLINDER
HEAD
INTAKE
MANIFOLD
When open
THERMOSTAT
EXHAUST
WATER JACKET
DRIVESHAFT
HOUSING
WATER TUBE
WATER PUMP
WATER INTAKE
WATER
PILOT WATER
HOLE