Jet Drive Model Identification And Serial Numbers - Yamaha T8 Rigging Manual

Outboard Rigging Guide - 2001
JET DRIVE MODEL IDENTIFICATION
AND SERIAL NUMBERS
Outboard Identification
See your Yamaha Outboard Motor Owner's
Manual for outboard and motor identification
number locations.
Jet Drive Identification
The Jet Drive Model Letter is stamped on the
rear, port-side casing. The Jet Drive Serial
Number is stamped on the starboard side of the
casing.
NOTE: The outboard motor and jet drive model
and serial numbers are important when you need
to have service performed or place an order for
parts. For easy reference, please record these
numbers on the inside front cover of your Yamaha
Outboard Motor Owner's Manual.
Application and Sizing
Hull Selection
Best performance is obtained by selecting a light,
shallow-draft hull, with a relatively flat (five-
degree angle, or less), wide bottom. Vee or Multi-
Vee hulls are not recommended (additional drag
would be placed on the jet drive's water intake
housing) because of their greater tendency to pro-
duce cavitation. Aluminum boats are preferred
because of their weight and durability. These
boats typically have optimum hull shapes, too.
As a rule, boat bottom width for your jet drive
should be at least 48", and centerline length at
least 13'.
NOTE: Transom height is especially critical for
jetdrive outboards, which are usually mounted 6"
to 7" higher than propeller-driven outboards;
therefore, it is advisable to use a full transom with
your jet drive.
Motor Selection
Motor Sizing
A boat operating at slow speed requires consider-
ably more depth than one that is planing on the
surface of the water. It is important, therefore, to
use sufficient horsepower and to not overload
your boat beyond its ability to plane. The accom-
panying graph is based on experience obtained
with sled-type boats, using an outboard-style jet.
Gross weights shown include the motor, hull,
fuel, passengers, and all gear. For a given horse-
power, loading beyond the listed limits will obvi-
ously give reduced performance.
Conversely, slight overpowering, based upon
anticipated load, will result in quicker planing,
reduced throttle settings for a given speed, and
subsequently, increased efficiency of operation.
NOTE: The performance output levels of jet
drive outboards do not reflect true performance
compared to propeller-driven outboards of the
same powerhead horsepower. The jet drive unit is
usually figured to have an output level equal to
70% of the propeller driven unit's. Keep in mind
that boat loading, weight, and hull configuration
can significantly affect the performance of your
jet drive outboard.
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Jet Drive Model Identification
& Serial Numbers