Propeller Selection; Break-In; Initial Break-In Procedure; Sterndrive 10-Hour Break-In Period (New Or With Replacement Gears) - Mercury TDI 4.2L Manual

Section 2 - On The Water

Propeller Selection

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.
It is the responsibility of the boat manufacturer and the selling dealer to equip the power package with the correct propellers.
IMPORTANT: 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 full load.
If full‑throttle operation is below the rated engine 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.
Break‑In
Initial Break‑In Procedure
It is especially important that the following procedure be used on new diesel engines. This break‑in procedure allows the proper
seating of the pistons and rings, which greatly reduces the likelihood of problems.
IMPORTANT: It is recommended 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 approximately 60‑seconds to allow the starter motor to cool; then, repeat the starting procedure.
1. See the appropriate Starting, Shifting, and Stopping section, and start the engine. Operate the engine at a fast idle until
it has reached normal operating temperature.
2. Operate the engine in gear for three‑minutes at : 1200 RPM, 2400 RPM, and 3000 RPM.
3. Operate the engine in gear for three‑minutes at: 1500 RPM, 2800 RPM, and 3400 RPM.
4. Operate the engine in gear for three‑minutes at : 1800 RPM, 3000 RPM, and maximum rated full throttle RPM.
Sterndrive 10‑Hour Break‑In Period (New or With Replacement Gears)
It is important that the following procedure be used on new sterndrives and rebuilt sterndrives with new replacement gears. This
break‑in procedure allows the proper seating of the sterndrive gears and related components, which greatly reduces the
likelihood of problems.
• Avoid full‑throttle starts.
• Do not operate at any constant speed for an extended period of time.
• Do not exceed 75% throttle during the first five‑hours. During the next five‑hours, operate at intermittent full throttle.
• The sterndrive should be shifted into forward gear a minimum of 10 times during break‑in, with run‑in time at moderate
RPM after each shift.
Engine Break‑In

20-Hour Break-In Period

IMPORTANT: The first 20 hours of operation is the engine break‑in period. Correct break‑in is essential to obtain minimum oil
consumption and maximum engine performance. During this break‑in period, the following rules must be observed:
• 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 any constant speed for an extended period of time.
• Do not exceed 3/4 throttle during the first 10 hours. During the next 10 hours, occasional operation at full throttle is
permissible (in five‑minute intervals).
Page 26
NOTICE
90-8M0114081 DECEMBER 2015
eng