Boat In The Water Tests - Mercury MX 6.2 MPI Installation Manual

INSTALLATION MANUAL

Boat In The Water Tests

IMPORTANT: Engine alignment MUST BE CHECKED with boat in the water, fuel tanks
filled, and with a normal load on board.
NOTE: On Tow Sports Applications: If during testing for a particular application, you
experience fuel starvation in sharp high speed turns, baffles or a fuel sump may be needed
in the tank to help correct this condition.
ENGINE IDLE SPEED ADJUSTMENT
Engine should idle at rpm (as specified in appropriate Mercury MerCruiser Operation, Main-
tenance and Warranty Manual) with boat in the water, drive unit in FORWARD gear and en-
gine at normal operating temperature. If idle speed is incorrect, proceed as follows:
1. Ensure that throttle cable has been adjusted properly.
2. If idle speed is still not correct, it may be necessary to perform EFI System Diagnostic
Tests on the idle circuit. Refer to the appropriate Mercury MerCruiser Service Manual
for procedures.
WIDE OPEN THROTTLE TEST
IMPORTANT: To run engine at full throttle before the break-in period is complete, fol-
low this procedure.
1. Start engine and run at idle rpm until normal operating temperature is reached.
2. Run boat up on plane.
3. Advance engine rpm (in 200 rpm increments) until engine reaches its maximum rated
rpm.
To test if the correct propeller has been installed, operate boat (with normal load on board)
at WOT and check rpm with an accurate tachometer. Engine rpm should be near top of the
specified range so that, under a heavy load, engine speed will not fall below specifications.
If engine speed is too high, replace propeller with a higher pitch propeller. Normally a 1 inch
propeller pitch change causes an rpm change of 150 rpm.
4. Shut off engine.
5. Check coolant level and add coolant if necessary.
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