Mercury 10/15 Sea Pro/Marathon - 6/8/9.9/10/15 HP User Manual page 82

3. Shift the outboard to forward gear while maintaining idle speed.
4. Turn the slow speed mixture screw slowly in until the engine starts to
misfire or stall due to a lean mixture. Not the position of the screw slot.
5. Turn the slow speed mixture screw slowly out until the engine start to
load up or fire unevenly due to a rich mixture. Not the position of the
screw slot.
6. Set the slow speed mixture screw midway between the rich and lean
setting. When in doubt, set the mixture slightly rich rather that too lean.
ENGINE IDLE SPEED ADJUSTMENT
1. Engines equipped with an adjustable idle speed screws:
a. With boat tied securely to dock, start engine and allow it to warm up.
b. Shift the outboard to forward gear while maintaining idle speed.
Make sure the primer/fast idle knob is pushed all the way in and
turned to the slowest idle speed.
c. Adjust the idle speed screw to obtain the recommended engine idle
speed. Refer to General Information - Specification.
2. Engines not equipped with an adjustable speed screw:
a. The carburetor has been calibrated for engine to run at the
recommended idle speed. The engine idle speed is not adjustable.
HIGH SPEED MIXTURE ADJUSTMENT
The carburetor is equipped with a standard size high speed fixed jet that
is replaceable for operation at higher elevations.
MAINTENANCE
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