Specifications

J/46 OWNER GUIDE
30
Fuel System
•
Fuel Tank & Hoses:
The J/46 is equipped with two fuel tanks for a total 90gallon capacity. The
primary 60gallon tank is located under the quarter-berth. A secondary tank is located on centerline aft
below the steering cables. This 30gallon tank gravity feeds into the primary tank. Fuel lines run from
the primary tank to the fuel primer pump. From there fuel flows into the injectors. The tanks
themselves are aluminum and baffled to prevent fuel slosh. The secondary fuel tank is designed to
allow conversion to accommodate an optional generator and/or heater. For a layout, please see the
Fuel System diagram.
•
Fuel Gauge:
is located under the wheel hub at the pedestal. The gauge reflects level (height) of fuel
in the primary tank, not the quantity. Try to maintain a minimum level of 1/3 to 1/2 tank filled at all
times.
•
Fuel Line Shut-Off Valve:
also sits atop the tank at its forward end. Since diesel engines require
bleeding after they have been deprived of fuel, it’s important that the shut-off valve be in the “ON”
position (lever parallel to piping) anytime the engine is started.
•
Fuel Tank Access Plate:
is atop each fuel tank and provides access inside to clean the tank or check
the fuel gauge.
Engine Cooling System
The engine utilizes a closed system in which a mixture of water and anti-freeze is circulated within the
engine for cooling. This liquid is cooled by a heat exchanger which uses sea water, in a similar fashion to
the radiator on a car which uses air to cool the contained liquid.
• The filler cap for the fresh water (closed) cooling system is located on top of the engine manifold, and
looks like a radiator cap. Check the level in the manifold frequently (ensure engine is cool). If
additional liquid is necessary, add only a mixture of anti-freeze/fresh water. In colder climates where
freezing may occur over the winter, be sure to test the coolant anti-freeze/water mixture for freezing
point and add anti-freeze as needed if the system is not drained for winter lay-up. Follow engine
manual recommendations for proper water/anti-freeze ratios.
• The WATER STRAINER is located in the engine compartment and has a two-stage design to prevent
“clogging” of the cooling system. Its simple design facilitates periodical cleaning. To clean: Ensure the
engine water intake thru-hull is closed. Check that the lever is perpendicular to the intake. Unscrew
the wing-nuts atop the filter and remove the strainer from inside the glass case. Wash thoroughly with
water or replace with a new one if badly soiled. Replace strainer into case and tightly affix lid with the
wing-nuts.
Exhaust System
The J/46 is equipped with a water-injected exhaust system which cools the exhaust. It is designed to both
dissipate heat and act as the exhaust muffler. If the flow of cooling water is interrupted and the engine
overheats severely, the rubber hose coming from the engine exhaust elbow may melt. Always check this
hose after an occurrence of overheating. Water can accumulate in the bottom of the muffler. In fall de-
commissioning, the pot should be drained using the drain plug, or anti-freeze added to the pot so residual
water doesn’t freeze. If the engine does not start after a prolonged period of cranking over (starting), be
sure to drain the pot or exhaust loop. Water accumulates here and may fill enough to flow back into
engine manifold if engine does not start.