Gasoline; Engine Oil; Propeller Selection; Start-In-Gear Protection - Yamaha 4AC Owner's Manual

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CAUTION:
Use only new clean gasoline which has
been stored in clean containers and is not
contaminated with water or foreign matter.
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Gasoline

Recommended gasoline:
Regular unleaded gasoline
If knocking or pinging occurs, use a different
brand of gasoline or premium unleaded fuel. If
unleaded gasoline is not available, then pre-
mium gasoline can be used.
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Engine oil

Recommended engine oil:
YAMALUBE 2-stroke outboard motor
oil
If the recommended engine oil is not avail-
able, another 2-stroke engine oil with an
NMMA-certified TC-W3 rating may be used.
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Propeller selection

The performance of your outboard motor will
be critically affected by your choice of propel-
ler, as an incorrect choice could adversely af-
fect performance and could also seriously
damage the motor. Engine speed depends on
the propeller size and boat load. If engine
speed is too high or too low for good engine
performance, this will have an adverse effect
on the engine.
Yamaha outboard motors are fitted with pro-
pellers chosen to perform well over a range of
applications, but there may be uses where a
propeller with a different pitch would be more
appropriate. For a greater operating load, a
smaller-pitch propeller is more suitable as it
General information
enables the correct engine speed to be main-
tained. Conversely, a larger-pitch propeller is
more suitable for a smaller operating load.
Yamaha dealers stock a range of propellers,
and can advise you and install a propeller on
your outboard that is best suited to your appli-
cation.
1. Propeller diameter in inches
2. Propeller pitch in inches
3. Type of propeller (propeller mark)
NOTE:
Select a propeller which will allow the engine
to reach the middle or upper half of the oper-
ating range at full throttle with the maximum
boat load. If operating conditions such as light
boat loads then allow the engine r/min to rise
above the maximum recommended range, re-
duce the throttle setting to maintain the en-
gine in the proper operating range.
For instructions on propeller removal and in-
stallation, see page 37.
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Start-in-gear protection

Yamaha outboard motors affixed with the pic-
tured label or Yamaha-approved remote con-
trol units are equipped with start-in-gear
protection device(s). This feature permits the
engine to be started only when it is in neutral.
Always select neutral before starting the en-
gine.
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