Mercury 40 Jet Manual page 59

The driveshaft driven impeller draws water up through the water
intake and then redirects it at a high pressure through the water
outlet nozzle to create forward thrust. To obtain reverse, the
reverse gate moves over the outlet nozzle to direct the water in the
opposite direction.
a - Water intake
b - Water outlet nozzle
When the jet drive is in neutral, the impeller continues to rotate.
However, the reverse gate is positioned so that some of the
forward thrust is diverted to create reverse thrust. This
approximate balancing of forward and reverse thrust will minimize
any boat movement. Because the impeller is always rotating and
creating thrust when the engine is running, the boat may tend to
move slowly forward or backward. This is normal for a direct‑drive
jet driven boat. The operator should be aware of this and use
caution whenever the engine is running.
Avoid injury resulting from contacting the rotating impeller or
having hair, clothing, or loose objects drawn into the water intake
and wrapping around the impeller shaft. Stay away from the
water intake and never insert an object into the water intake or
water outlet nozzle when the engine is running.
OPERATION
c
a
WARNING
!
51
b
29022
c - Reverse gate