Mercury MerCruiser Service Manual page 427

4. Heat the water.
5. Stir the water constantly to avoid applying direct heat to the thermostat.
b
a
6. Observe the thermostat and check the temperature when the thermostat fully opens. If the temperature is not within
specifications, then replace the thermostat.
Thermostat Installation into the Crossover
NOTE: Refer to the exploded view for parts identification.
1. Clean the gasket surfaces on the crossover, thermostat cap, and thermostat.
2. Place a new thermostat housing gasket in the crossover. Ensure that it is positioned properly in the opening.
3. Place the thermostat in the opening in the crossover with the thermostatic element end toward the bottom.
4. Position a new thermostat cap gasket on the crossover.
5. Install the thermostat cap and tighten the screws to the specified torque.
Description
Screws
Without sufficient cooling water, the engine, the water pump, and other components will overheat and suffer damage. Provide
a sufficient supply of water to the water inlets during operation.
6. Supply cooling water to the engine.
7. Start the engine and inspect for leaks.
90-8M0099748 eng DECEMBER 2015
c
d
NOTICE
© 2016 Mercury Marine
Models with Standard Cooling
a - Wooden blocks
b - Stirring rod
c - Thermometer
d - Thermostat
50079
Nm
27.1
lb‑in. lb‑ft
– 20
Page 6B-3