Mercury INSTALLATION MANUAL D7.3L D-TRONIC - Manual (Page 79)

D7.3L D-TRONIC DIESEL ENGINES - BRAVO MODELS
Page 79 of 90
Boat-In-The-Water Tests
IMPORTANT: Engine alignment MUST BE CHECKED with boat in the water, fuel tanks
filled, and with a normal load onboard.
IMPORTANT: DO NOT perform the following with boat in a test tank or tied to dock.
ENGINE 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 low hour problems.
IMPORTANT: It is recommended that the boat not be accelerated hard until this proce-
dure has been completed.
Initial Break-In Procedure is as follows:
1. Start engine and run at idle until coolant has reached minimum operating temperature
150 ° F (65 ° C).
2. Run engine in gear for 3 minutes at each of the following rpms: 1200 rpm, 2400 rpm and
3000 rpm.
3. Run engine in gear for 3 minutes at each of the following rpms: 1500 rpm, 2800 rpm and
3400 rpm.
4. Run engine in gear for 3 minutes at each of the following rpms: 1800 rpm, 3000 rpm and
Maximum Rated Full-Throttle rpm.
MAXIMUM RPM TEST
Power package should be equipped with a propeller that will allow engine to operate at its
specified maximum wide-open-throttle revolutions per minute (rpm), with an average load
aboard the boat. Best all around performance is obtained with the D7.3L D-Tronic engine
propped at 3800 rpm and the D7.3L D-Tronic engine propped at 3600 rpm.
IMPORTANT: Consider this additional information:
The engines listed in the following chart are equipped with an electronic device that
limits engine rpm. Be sure that propeller being used does not allow engine to run
against the device, as a significant loss in performance will result.
Engine rpm
MCM Model
Engine Recommended
Operating rpm Range
Engine rpm Limiter Setting
(Begins At:)
D7.3L D-Tronic 3600-3800 3850
D7.3L D-Tronic LD 3400-3600 3650
To check that the correct propeller has been installed, operate the boat with a light load (one
person, fuel tank half full) at wide-open-throttle and optimal trim. (Optimal trim is the point
where boat speed no longer increases when trimming-out. High rpm caused by excessive
trimming should not be used when checking for correct propeller.) rpm should be near the
top of specified range so that under a heavy load, engine speed will not fall below specifica-
tions. If engine speed is too high, replace propeller with one that has a higher pitch. If engine
speed is too low, replace with a lower pitch propeller. Generally, there is a 200 rpm change
between propeller pitches.
If a propeller cannot be obtained that will place the engine in the proper rpm range, it may
be necessary to have the propeller reworked at a propeller repair station.