Mercury 75 Operation Maintenance Warranty Installation Manual page 79

It is possible for debris to lodge between the impeller and jet housing wall,
especially after the engine has been stopped. This will lock the driveshaft and
will prevent the engine from being able to crank over for starting. Following are
steps for dislodging the impeller.
1. Position the lanyard stop switch to the "OFF" position.
2. Remove the spark plug leads to prevent the engine from accidentally
starting.
3. Remove the flywheel or rewind cover and rotate the engine flywheel
counterclockwise.
If this does not dislodge the impeller, it will be necessary to remove the six
screws and water intake housing.
STARTING THE ENGINE
Before starting, read the prestarting check list, special operating instructions,
and engine break‑in procedure in the Operation section.
NOTE: When the engine is being run within the RPM range of 3500–4200
RPM, there may be a slight RPM instability. This is caused by the light engine
load conditions normally seen with jet lower units. This condition will not cause
any adverse affects on the engine.
Without sufficient cooling water, the engine, the water pump, and other
components will overheat and suffer damage. Provide a sufficient supply of
water to the water inlets during operation.
1. Ensure that the driveshaft bearing on the jet drive is lubricated. Refer to
Maintenance ‑ Lubrication Points.
2. Open the fuel tank vent screw, located in the filler cap, on manual venting
type fuel tanks.
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OPERATION
NOTICE
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