v1.0
23 - Fuel System
Viking Sport Cruiser 61FY
Owner’s Manual
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Fuel System: Overview
Tanks and fuel lines
Fuel capacity is 790 gal U.S., held in four welded alumi-
num tanks in the engine room connected as port and star-
board pairs. Each pair comprises a wing tank and a con-
nected fwd bulkhead tank. Each pair (port and starboard)
acts as a single tank because of a normally open balance
pipe connection between them. There is no connection,
however, between port and starboard sides. Tanks have in-
ternal baffles to add strength and reduce sloshing of fuel
in a seaway.
Each side is filled separately (into the wing tank). And each
side supplies one engine only. The starboard tank also sup-
plies the generator.
Pumps on the engines draw fuel from the tanks. More fuel
is pumped to the engines than they can burn (to avoid
fuel starvation). Unburned fuel returns to its tank of origin
via the fuel return lines. The return fuel is warmed by its
passage through the engine and thus it carries heat back
to the main tanks which gradually get warmer and warmer.
This residual heat in the tanks, as it cools, can result in
condensation on the tank walls which, combined with infil-
trating oxygen from the vents, can promote bacterial growth.
Use antibacterial additives, and keep tanks well filled. Moni-
tor filters for water, dirt, and bacterial debris.
A vent from each tank allows air to escape or enter. If the
tank is overfilled fuel will spill out the vent, particularly
with boat motion, so do not overfill the tanks (see the
section in this chapter on Refueling The Vessel).
Control valves
Remote fuel shut-offs,
A
, are installed on the top of
both tanks. They are operated from the deck service
locker, starboard side (shown in inset). The valves are
for safety – they enable the fuel supply to be shut off
for both engines and the generator.
If you close any of these valves you must ensure that
the engines or generator cannot be started until the
valve is opened again.
Tank top valves (shown open)
Generator
Engine
Remote fuel shut-offs
B
– Port engine
C
– Starboard engine
D
– Generator
These are in the starboard
cockpit service locker and
operate the tank top valves.
Typical
Leaking fuel is a fire hazard. Inspect
system regularly and correct any
leakage problems before operating
the vessel.
B
C
A
D
Fuel supply, port
Fuel supply, starboard
Fuel returns
Balance pipe, port
Balance pipe, starboard
