Beta Marine Beta 10 Operator's Maintenance Manual page 35

Problem: Vibrations
Possible Cause
Poor alignment to shaft:
Flexible mounts not adjusted correctly to take even weight:
Flexible mount rubber perished:
Loose securing nut on flexible mount:
Insufficient clearance between the propeller
tip and the bottom of the boat:
Loose zinc anode on the shaft:
Worn cutless bearing or shaft:
Weak engine support/bearers:
Problem: Knocking noise
Possible Cause
Propshaft touching gearbox output coupling
through split boss or Type 16 coupling:
Flexible mount stud touching engine bed:
Drive plate broken:
Engine touching engine bed:
Injectors blocked through excess carbon
caused by water in the fuel:
Solution
The alignment must be accurate even if a flexible
coupling is used (see section 1, Alignment).
Check relative compression of each mount.
Replace. (Diesel or oil will eventually perish
most rubbers.)
Check alignment and then tighten the nuts.
There must be at least 10% of the propeller diameter
as tip clearance between the propeller and the bottom
of the boat. Reduce propeller diameter / increase pitch.
Tighten or replace.
Replace.
Check for cracked or broken feet.
Solution
Adjust, giving correct clearance give 5mm - 10mm
between gearbox and propeller shaft
Adjust stud to clear
Replace / repair
Re-align engine / modify bed
Remove and check injector nozzles, replace if required.
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