Caution: This document contains mixed page sizes ... - Cummins Onan

Fuel Return Line (Genset to Supply Tank)
• Tubing: Use 1/4 inch O. D. (± 0.003 inch)
welded and drawn Type 304L stainless or
AISI 1008−1010 low carbon steel tubing of
0.028 inch minimum wall thickness. The tubing
must meet requirements for 150 psi operating
pressure (Ref. ASTM A 539−99) and have corrosion
resistance equal to or better than hotdipped
zinc galvanization.
• Hose Beads: Use suitable tooling to form tubing
ends into SAE J1231 Type 1 or Type 3
double-flare hose beads (Figure 4-4). This is
recommended for all return tubing and fittings.
• Flexible Hose: Use 1/4 in I. D. fuel hose meeting
SAE J30R9 standards for working pressure
and applicable standards for evaporative emissions.
CAUTION When connecting fuel hoses,
only use soap-free lubricants such as
WD40, which runs through fuel without
leaving residues that can clog fuel jets.
• Hose Clamps: Use stainless steel stepless ear
clamps (Figure 4-4). Onan P/N 0503-1951-11,
Oetiker P/N 16700011 or equivalent are recommended.
Routing Fuel Lines
Route the supply and return lines side-by-side along
bulkheads and frame members such that they are
protected. They should be at or above the top of the
fuel tank to reduce siphoning if a line breaks or a
hose comes off. The entire length of the fuel lines
must be visible for inspection and accessible for replacement.
Support fuel lines to restrain movement and prevent
chaffing or contact with sharp edges, electrical wiring
and hot exhaust parts.
WARNING Electric arcs can ignite gasoline
leading to severe personal injury or death. Do
not run wiring and fuel lines together.
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