MJM Yachts 34z Express User Manual
Page 19
CHAPTER 5
FUEL SYSTEM
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34z
5.1 GENERAL
It is important to understand the fuel system aboard your boat. Diesel fuel is different than
gasoline. In most respects it is safer, however precautions need to be taken to maintain the safety
of your boat. Please study the safety precautions in the NMMA publication “Sportfish, Cruisers,
Yachts – Owner’s Manual.”
Diesel engines need to intake more fuel than they burn, and so they differ from gasoline engines
in that they return excess fuel to the tank. Both feed & return are to the starboard fuel tank.
Hull #23 and higher have fuel tanks which are connected by a “leveling” fuel line with an isolating
shut-off shown below. The tanks equalize automatically.
5.2
FILLING THE TANKS
Deck fills are mounted on the side decks, port & starboard, and are labeled “DIESEL.” Each one
services only its respective tank, although with the connecting fuel line valve open, you will get
some transfer to the opposite tank. As the tank is filled, vapor escapes the tank thru the vent.
Overflow is prevented by an in-line fuel/air separator that will not allow fuel to pass. However,
caution should be taken while filling. Check the fuel level gauges and listen for the rise in pitch at
the deck fill, as fuel reaches the top. Shut off the nozzle immediately. Do not attempt to “top off”
the tanks. Variations in temperature as well as trim angle could cause overflow or vent-line
blockage.
PRIMARY RACOR FUEL FILTER. If your boat has
an optional diesel generator, the generator’s
smaller Racor Fuel Filter is located next to this one.
ENGINE RAW WATER SEACOCK IN OPERATING
POSITION..
Do not push handle to floor.
Keep at 90 degrees or intake water will be restricted
.
BRIDGE-DECK
UP/DOWN
SWITCH
FUEL SHUT-OFF ACCESS
PORT (Starboard Side Only)
ENGINE AIR
INTAKE VENTS
P&S
CONNECTING FUEL LINE TO
LEVEL P&S TANKS & SHUT-
OFF VALVE SHOWN CLOSED
(NORMALLY LEFT OPEN).
PRESSURE
WATER
OUTLET
HOSE CONNECTION ON TOP OF SEACOCK TO FLUSH
ENGINE OR SERVE AS EMERGENCY BILGE PUMP