Section 2 - On the Water
90-8M0113986
eng
DECEMBER 2015
Page 21
Propeller Selection
NOTICE
Operating the engine with the wrong propeller installed can limit power, increase fuel consumption, overheat the engine, or
cause internal powerhead damage. Choose a propeller that allows the engine to operate at the specified wide open throttle
RPM.
The boat manufacturer and the selling dealer are responsible for equipping the power package with the correct propellers.
IMPORTANT: The engines covered in this manual are equipped with an ECM that limits engine RPM. Be sure that the propeller
being used does not allow the engine to run against the limiter, as a significant loss in performance will result.
NOTE: Use an accurate service tachometer to verify RPM.
Select a propeller that will allow the engine power package to operate at the rated engine RPM with a maximum load.
If full throttle operation is below the engine rated RPM, the propeller must be changed to prevent loss of performance and
possible engine damage. On the other hand, operating an engine above the rated engine RPM will cause higher than normal
wear or damage.
After initial propeller selection, the following common problems may require that the propeller be changed to a lower pitch:
•
Warmer weather and greater humidity cause an RPM loss (not as significant on these models).
•
Operating in a higher elevation causes an RPM loss (not as significant on these models).
•
Operating with a damaged propeller or dirty boat bottom causes an RPM loss.
•
Operating with increased load (additional passengers, pulling skiers).
For better acceleration, such as is needed for water skiing, use the next lower pitch propeller. Do not operate at full throttle
when using the lower pitch propeller but not pulling skiers.
Getting Started
Initial Break‑In Procedure
It is important to follow this procedure to properly break in the engine.
IMPORTANT: Mercury Marine recommends that the boat not be accelerated hard until this procedure has been completed.
IMPORTANT: Never operate the starter motor longer than 15 seconds at a time to avoid overheating the starter motor. If the
engine does not start, wait one minute to allow the starter motor to cool; then, repeat the starting procedure.
1. Refer to the appropriate
Starting, Shifting, and Stopping
section and start the engine.
2. Operate the engine at a fast idle until it has reached normal operating temperature.
3. Operate the engine in gear for three minutes at each of the following: 1200 RPM, 2400 RPM, and 3000 RPM.
4. Operate the engine in gear for three minutes at each of the following: 1500 RPM, 2800 RPM, and 3400 RPM.
5. Operate the engine in gear for three minutes at each of the following: 1800 RPM, 3000 RPM, and maximum rated full
throttle RPM.
Engine Break‑In
20-Hour Break-In Period
IMPORTANT: The first 20 hours of operation are considered to be the engine break‑in period. Correct break‑in is essential to
obtain minimum oil consumption and maximum engine performance. During this break‑in period, observe the following rules:
•
Do not operate below 1500 RPM for extended periods of time for the first 10 hours. Shift into gear as soon as possible after
starting, and advance the throttle above 1500 RPM if conditions permit safe operation.
•
Do not operate at one constant speed for extended periods.
•
Do not exceed 3/4 throttle during the first 10 hours. During the next 10 hours, occasional operation at full throttle is
permissible (five minutes at a time maximum).
•
Avoid full‑throttle acceleration from idle speed.
•
Do not operate at full throttle until the engine reaches normal operating temperature.
•
Check the engine oil level frequently. Add oil as needed. High oil consumption is normal during the break‑in period.
After the 20-Hour Break-In Period
To help extend the life of your power package, Mercury Marine recommends the following:
•
Change the engine oil and filter and the transmission fluid at the interval indicated in the
Maintenance Schedule
. Refer to
Specifications
and
Maintenance
.
•
Use a propeller that allows the engine to operate at the rated engine RPM when at full throttle with a fully loaded boat.
Refer to
Specifications
and
Maintenance
.
Summary of Contents for 92-8M0069603
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