Generac Power Systems quietpact 85d, Owner'S Manual

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Because diesel fuels are less volatile than gasoline or gaseous
fuels, they are considered safer from the standpoint of storage
and handling. As a result, installers may tend to be careless in
their installation practices, which can result in poor engine per-
formance. For example, a poorly tightened fuel line may not show
any signs of leakage; however, air can be drawn into the loose
connection and cause problems. Air that is trapped in the diesel
fuel system results in hard starting and rough engine operation.
Dirt that enters the fuel system also may cause problems. Lines
and piping must be properly installed and tightened to prevent dirt
from entering. Diesel fuel must be kept clean.
Factory-installed generator fuel system components include (a) a
fuel filter, (b) a 12-volt DC electric pump, (c) an injection pump,
and (d) interconnecting lines and fittings. Connect a fuel supply
line to the supply fitting and a return line from the fuel return fitting
back to the tank.
NOTE:
Fuel supply and return fittings located on the generator are 1/8”
NPT.
Use a length of approved flexible fuel hose between the fuel con-
nection fittings and rigid fuel lines (see the Generator Fuel Supply
Lines" and "Generator Fuel Return Lines" sections.
2.4.1 FUEL TANK
Either the generator must share the vehicle’s engine fuel tank, or a
separate fuel tank for the generator set must be installed. All fuel
tanks installed on the vehicle must be constructed, installed, and
restrained so they comply with applicable codes, standards, and
regulations.
If the generator is to share the vehicle’s engine tank, separate
fuel pickup tubes are required for the engine and the generator.
The manufacturer recommends that the fuel pickup tube be two
to three inches (51 to 76 mm) shorter than the vehicle’s engine
pickup tube. This prevents the generator from depleting the entire
fuel supply during prolonged generator operating periods.

DO NOT tee the generator fuel supply line
into the vehicle engine fuel supply line. If
this is done, the generator will be starved of
fuel when both engines are operating at the
same time. Also, while the vehicle engine is
not running, generator operation may drain
the vehicle engine supply line, making it dif-
ficult to start the vehicle engine.
2.4.2 GENERATOR FUEL SUPPLY LINES
Rigid Fuel Lines
Those lines used to supply fuel from a tank to the generator must
comply with applicable codes, standards, and regulations. The
following general rules apply to rigid fuel lines:
• Rigid lines should be of annealed, seamless, drawn aluminum,
or steel.
• Lines and fittings must comply with SAE J512F, “Standard
Automotive Fittings,” or with ANSI B126.26 (latest edition).
• Route the fuel line so that at least 2 inches (51 mm) of clear-
ance is maintained between the line and any exhaust system
parts.
• Do not attach electrical wiring to fuel lines. Route the wiring so
it cannot come into contact with any fuel line.
• Route fuel lines so that, if they leak, fuel does not drip onto any
electrical or exhaust system parts.
• Use nonferrous metal straps without sharp edges to secure
fuel lines.
• Fuel system components must be accessible, but protected
from abrasion, chafing, road damage, and kinking.
Flexible Fuel Line
Use a length of approved flexible fuel hose between the generator
fuel supply fitting and rigid fuel lines. This prevents breaking of
the line caused by vibration, shifting, settling, or movement. The
following rules apply:
• The flexible hose must comply with SAE J1137 (30R7),
“Standard for Fuel and Oil Hose.” It must be approved for use
with diesel fuel and low permeability.
• The hose should be at least 6 inches (152 mm) longer than
is needed, to prevent the hose from rupturing if the generator
shifts or settles.
2.4.3 GENERATOR FUEL RETURN LINES
The same general rules that apply to fuel supply lines also apply
to fuel return lines.
NOTE:
Locate the diesel fuel return line at least 12 inches from the
tank fuel pickup tubes to prevent air bubbles from entering the
fuel supply lines.
Installation