Mercury 8.1S Horizon, Product Applications Manual

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Transmission and Drive Line
Page 2A-4 90-863758060 AUGUST 2006
Description Nm lb. in . lb. ft.
Coupler bolts 68 50
Propeller Shaft
The required propeller shaft diameter can vary significantly depending on the material
used, strut and bearing design, engine horsepower, and shaft RPM. Information is available
from the propeller shaft manufacturer and in marine handbooks for selecting the proper
diameter. Sufficient shaft diameter is critical for durability and minimizing vibration. As a
guideline, the propeller shaft should be a minimum of 1/14 the diameter of the propeller.
Propeller Shaft Log Seal Connections
!
CAUTION
Avoid overheating damage. Mercury MerCruiser is not responsible for engine damage
caused by improper cooling system connections for the propeller shaft log seal.
The propeller shaft log seal hose should be routed so that a portion of the hose extends
above the top of the engine exhaust elbows to prevent a siphoning action when the engine
is not running. Securely fasten the hose to maintain its proper position.
!
CAUTION
Engine damage may result from failure to route propeller shaft log seal hose properly.
This could cause increased exhaust system corrosion, submersion damage or freeze
damage to engine.
8.1S MODELS
Connect the shaft log seal hose to the reducer fitting on the end of the starboard exhaust
manifold. The reducer fitting has been carefully sized to maintain the proper pressure
balance in the cooling system and must not be removed.
a
8426
Propeller shaft log seal connection — 8.1S models
a - Reducer fitting