Propeller Shaft; Propeller Shaft Log Seal Connections - Mercury MerCruiser Product Applications Manual

Transmission and Drive Line
Description
Coupler bolts

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

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.
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.
Page 2A-4
a
Propeller shaft log seal connection — 8.1S models
a - Reducer fitting
Nm lb. in.
68
CAUTION
!
CAUTION
!
8426
90-863758060 AUGUST 2006
lb. ft.
50