52 Sedan Bridge
(525 Sedan Bridge)
4.6
S
ECTION
4 • B
ILGE
& U
NDERWATER
G
EAR
10. V
IBRATION
& C
AUSES
Some vibration is to be expected in your boat
because of the action of the engines and the propeller.
But excessive vibration indicates conditions which
must be promptly corrected to avoid damage.
Contact your Sea Ray
®
dealer immediately if you
are experiencing severe vibration. The following are
some conditions which may cause vibrations.
A. F
OREIGN
O
BJECT
I
NTERFERING
W
ITH
P
ROPELLER
A
CTION
Weeds, ropes, fishing lines or nets can become
wrapped around the propeller and/or shaft, causing
vibration and loss of speed. Always stop and then
reverse the propeller after going through a weedy
area to unwrap and clear away any weeds which
may have accumulated. Although reversing will
sometimes help to unwrap lines and nets, they are
difficult to remove without hauling the boat.
Always check for loose or trailing dock lines before
getting underway. When towing a dinghy, remember
that a long line may easily become entangled with
the propeller when backing down.
Shut off the fuel lines and close the engine
seacocks. Remove all electrical wires, fuel lines
and raw water intake hoses from the engine. Unbolt
the engine coupling from the shaft coupling and slide
the shaft and coupling back from the engine. Detach
both throttle and shift connections. Cap off hoses
to avoid hydraulic fluid loss. Do not bend or twist
the hoses, as damage may result. Remove the
mounting bolts for the engine and lift the engine out,
leaving the mounts bolted to the stringer caps.
To reinstall, reverse the above procedure. Check
the coupling and shaft alignments, as well as water
hoses and wiring connections. Also check for fuel
and exhaust leaks and make sure seacocks are
open before starting engines.
B. B
ENT
P
ROPELLER
AND
/
OR
S
HAFT
A badly damaged or distorted propeller or shaft is
an obvious cause of vibration. Even when the
propeller appears to be perfect, make sure it has
not been pulled off-center by the propeller key.
C. E
NGINE
AND
S
HAFT
O
UT
OF
A
LIGNMENT
Although the shaft is properly aligned when it leaves
the factory, after transit and after the boat has been
in the water a few days, the alignment should be
rechecked. The shaft coupling is the connecting
point between the shaft and the engine and the
alignment should be set at .005 or less. Refer to
SHAFTS (pg. 4.10) in this section of this Owner’s
Manual.
D. C
OUPLING
O
UT
OF
T
RUE
Although an extremely unlikely condition, check the
couplings if other efforts to correct the vibration fail.
Check the engine half of the coupling (with dial
indicator on the face) to see that it runs true with
the shaft coupling. Also check the coupling keys.
They must fit correctly to prevent forcing the
couplings off center.
E. E
NGINE
P
ART
H
ITTING
B
OAT
S
TRUCTURE
Engines are flexibly mounted to reduce transmission
of vibration to the hull structure. If some part of the
engine, such as the oil pan, reverse gear or
reduction gear housing, contacts a stringer, brace
or part of the hull, vibration will result. The flexible
shaft log allows a limited side motion of the shaft,
but an excessive “whip” can cause the shaft to strike
the sides of the shaft hole or the shaft log with
resultant vibration.
F. O
THER
P
OSSIBLE
C
AUSES
Other causes of vibration include the following:
engine out of tune, a bent rudder, a worn strut
bearing, a component of the exhaust system
vibrating against the hull or improper contact
between shaft taper and the propeller hub bore.
Hose clamps must be tight at all times to avoid
exhaust leaks.
!
WARNING
