Yamaha T8 Rigging Manual page 80

Outboard Rigging Guide - 2001
Maintenance, Lubrication, and Storage
General
Occasionally, check all mounting bolts, intake
screws, linkage connections, etc., to be sure they
are tight.
Bearing Lubrication
The need for frequent lubrication of your jet drive
outboard cannot be overemphasized. We recom-
mend lubrication after each day's use and
every 10 hours of operation. Make greasing a
regular part of your cleanup. Use only
Yamalube Marine grease, or NLGI No. 1-rated
grease with a suitable grease gun.
The bearing lubrication fitting is located at the
top-left-front of the jet drive casing. It is capped
with a fitting on the end of the excess-grease exit
hose. Pump in enough grease to just fill the hose.
To remove the hose from the fitting, press the end
cap upward and toward the casing; to refit it, press
the hose end cap over the fitting.
Every 50 hours, pump in enough extra grease to
purge any moisture. The texture of the old grease
coming out of the hose will provide you with an
indication of conditions inside the bearing hous-
ing. (A gradual increase in moisture content indi-
cates seal wear.) If the grease begins to turn a
dark, dirty gray, the bearing(s) and seals
should be inspected and replaced as necessary.
Some discoloration of the grease is normal dur-
ing the break-in period on a new set of seals.
Impeller Clearance Setting
When, after use in a watercourse whose bottom is
sand and gravel, the clearance between the
impeller edge and the water intake casing wall
becomes more than about 1/32", one or more of
the shim washers that space the impeller can be
transferred from the stack underneath to the top of
the impeller. This locates the impeller further into
the tapered casing to reduce the clearance. Be sure
to grease the shaft hole in the impeller, the key,
sleeve, and shaft threads any time it becomes nec-
essary to remove the impeller.
NOTE: Your jet drive is equipped with a shear
key to protect it in the event of a rock jam. This
can be located by removing the water intake hous-
ing and the drive shaft nut. The key holds the jet
drive impeller on the driveshaft. This operation is
Jet Drive Eng. Mtg., Maintenance,
Shift Cable Instruction, Service Info.
similar to that on a propeller drive. After replacing
the key, draw the shaft nut up tight (17 ft-lb.) to
remove any play between the impeller and shaft.
Note the position of the impeller shim washers
and replace them in the same order as removed.
Linkage Adjustment
Occasionally, check the adjustment of the shift
linkage. In "Forward", the reverse gate should be
firmly locked. This will eliminate rattle, and pre-
vent wave action from accidentally shifting the
gate into reverse. (See "ADJUSTMENTS" [page
2-27] for the proper procedures.)
Salt Water Operation
Both aluminum and stainless steel have been
extensively used in the construction of your jet
drive. These and other materials have been either
treated or are inherently resistant to corrosion. In
addition, the intake grille, special key, and
exhaust tube are galvanized to further minimize
corrosion. It is recommended, however, that,
when not to use, the motor be tipped up so the jet
drive casing is out of the water.
CAUTION:
When your jet drive is used in
salt water more than in fresh, remove all
mounting hardware, and grease it at least once
every six months. Failure to do this may result
in the hardware being difficult, if not impossi-
ble, to remove at a later date.
NOTE: To facilitate removal of an impeller that
has frozen to the driveshaft, use a hammer and a
block of wood, and tap the impeller blades in the
direction of engine rotation. This will release the
shear key.
NOTE: A slightly distorted shear key may be
reused.
Storage
Consult your regular Owner's Manual for prepar-
ing the motor part of your jet drive for storage. In
addition, clean and grease all hardware, and
remove and refit the jet drive impeller, greasing
the bore, key, and plastic sleeve.
2-17