Mercury MerCruiser Diesel Inboard 2.8L Operation & Maintenance Manual Download

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Section 2 - On the Water

90-8M0133679

eng

JUNE 2017

Page 23

Marine vegetation may accumulate when the boat is docked. This growth must be removed before operation; it may clog water

inlets and cause the engine to overheat.

Elevation and Climate

NOTE: Engines equipped with an Engine Control Module (ECM) reduce the effects of changes in elevation and climate by

automatically adjusting fuel flow for weather conditions and elevation. ECM controlled engines, however, do not compensate for

increased loading or hull conditions.

Elevation and climate changes affect the performance of your power package. Loss of performance can be caused by:
•

High elevations

•

High temperatures

•

Low barometric pressures

•

High humidity

For optimum engine performance under changing weather conditions and high elevation, use a propeller that allows the engine

to operate at rated RPM at wide‑open throttle (WOT) with a maximum boat load during your normal boating.
In most cases, the rated RPM at WOT can be achieved by changing to a lower pitch propeller.

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 waterskiing, 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.