CONDITIONS AFFECTING OPERATION
40
•
A damaged propeller or gear housing, allowing exhaust gases to
escape between propeller and gear housing.
•
A drive unit installed too high on the transom.
Propeller Selection
IMPORTANT: Choosing the correct propeller allows the engine to run at
its specified maximum wide‑open‑throttle RPM. Use an accurate service
tachometer to verify engine operating RPM.
It is the boat manufacturer and/or the selling dealer's responsibility to equip
the power package with the correct propeller(s). Specified engine
wide‑open‑throttle (WOT) and operating RPM range are listed in
Specifications.
IMPORTANT: All Mercury Racing engines have a RPM rev‑limiter that is
set to an upper (or limited) RPM. This limit is slightly above the normal
operating range of the engine and is designed to help prevent damage from
excessive engine RPM. Once the RPM drops into the recommended
operating RPM range, normal engine operation resumes.
Select a propeller that allows the engine to operate in the upper half of the
recommended full throttle RPM range with the boat normally loaded (refer
to Specifications).
If full throttle operation is below the recommended range, change the
propeller to prevent loss of performance and possible engine damage. On
the other hand, operating an engine above the recommended operating
RPM range causes higher than normal wear or damage. Generally, there
is a 200 ‑ 300 RPM change between propeller pitches.
RPM loss may require changing to a lower pitch propeller due to the
following conditions:
•
Operating in warmer weather and greater humidity.
•
Operating in a higher elevation.
•
Operating with a damaged propeller or dirty boat bottom.
•
Operating with increased load (additional passengers, pulling skiers,
etc.).
Conditions That Lower Engine Performance
The following conditions lower engine performance and cannot be
compensated by the engine fuel or electronic management systems.
•
Above sea level elevations
•
High temperature.
•
Low barometric pressure.
Summary of Contents for HP1075 SCi
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