Checks Made With Boat Out Of Water And Shaft Installed - Mercury MerCruiser MCM 454 Mag MPI Service Manual

DRIVE SHAFT / PROPELLER SHAFT MODELS

Checks Made With Boat Out Of Water And Shaft Installed

Possible causes for vibration may be propeller shaft, propeller to shaft fit or propeller. All
three can be checked by using the rudder, a strong metal straight edge and a C- clamp.
1. Check installation of propeller to shaft.
a. Remove propeller.
b. Check for chipped or cracked keyway in propeller on shaft without key.
c. Install propeller on shaft without key.
d. Mark the shaft (behind the propeller), then remove propeller.
e. Install the key and propeller. Make sure propeller still lines up with mark. This
f.
2. Check for propeller shaft being bent behind the strut.
3. Check the diameter of all propeller blades. If not the same, repair propeller.
Index
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ensures that key is not oversize and holding the tapers apart. Retighten propeller
nut.
Be sure key is not sticking out of propeller.
b
a - Metal Straight Edge (Held To Rudder With C-Clamp) - Position Corner Of
Straight Edge At Center Of Shaft. Rotate Shaft One Complete Turn. If Shaft
Wobbles, Replace Shaft.
b - Rudder
b
a - Metal Straight Edge (Held To Rudder With C-Clamp)
b - Rudder
c - Rotate Propeller One Complete Turn
a
a
c
SERVICE MANUAL NUMBER 23
90-861326--1 MARCH 1999