Kohler 3.5CFZ, 4CZ, 5CFZ, 6.5CZ Anti-Siphon Provisions, Fuel Lines, 8. Fuel Pump Inlet Connection

Anti-Siphon Provisions

Anti-siphon devices must be installed if any section of fuel line lies below the highest point of the fuel tank. The anti-siphon device should be either a spring-loaded check valve (tested to function with the particular installation’s siphon head), or an electrically operated shutoff valve (UL ignition-protected, tested to U.S.C.G. Regulations) which may be operated manually. A check valve should be installed at a point above fuel tank’s highest point, secured to craft’s structure, and be accessible without removing any permanent structure. The fuel line section between the tank and check valve must be located above the tank’s highest point. An electric shutoff valve should be installed at the tank’s fuel withdrawal fitting, and be wired to open when the generator set engine is cranking or running.

Anti-siphon holes drilled in fuel dip tubes within the tank are not reliable anti-siphon devices as they become ineffective when restricted by dirt or gum.

Fuel Lines

Metallic lines should be used from the tank to a flexible hose section connecting metallic line to the engine fuel pump. Metallic lines must have wall thickness of at least 0.029 in. (0.74 mm). Seamless annealed nickel copper, copper-nickel, or copper tubing must be used. The flexible section (necessary to allow vibrational motion of the generator set during operation) must be U.S.C.G. TYPE A HOSE, marked and tagged according to Regulations. Metallic line must be supported within 4 in. (102 mm) of its connection to the flexible section. See Figure 6-8 for fuel pump inlet connection.

1

2

258000-D

1. 1/4 in. NPT Female	2. Electric Fuel Pump
Pipe Thread

Figure 6-8. Fuel Pump Inlet Connection

Any in-line fuel filters or strainers must conform to U.S.C.G. Regulations, must be independently mounted to the craft’s structure, and must be accessible for servicing without removing any permanent structures.

NOTE

If a fuel strainer is installed, each fuel filter and strainer must be supported on the engine or boat structure independent from its fuel line connections, unless the fuel filter or strainer is inside a fuel tank.

Fuel Pump Lift Capabilities and

Fuel Consumption

Figure 6-9 lists electric fuel pump lift capabilities and fuel line sizes. Figure 6-10 shows generator set fuel consumption rates.

Model	Fuel Pump	Fuel Inlet Size
	Max. Lift ft. (m)	I.D. in. (mm)
3.5CFZ	3 (0.9)	3/8	(9.5)
4CZ	3 (0.9)	3/8	(9.5)
5CFZ	3 (0.9)	3/8	(9.5)
6.5CZ	3 (0.9)	3/8	(9.5)

Figure 6-9. Fuel Pump Lift and Fuel Line Size

	Load and GPH (L/hr.)
Model	1/4	1/2	3/4	Full
3.5 CFZ	0.42	0.50	0.59	0.68
	(1.59)	(1.89)	(2.23)	(2.57)
4CZ	0.48	0.55	0.62	0.68
	(1.81)	(2.08)	(2.34)	(2.57)
5CFZ	0.44	0.54	0.66	0.80
	(1.67)	(2.04)	(2.50)	(3.03)
6.5CZ	0.53	0.62	0.86	1.02
	(2.00)	(2.34)	(3.25)	(3.86)

Figure 6-10. Fuel Consumption

6-6 Installation TP-5695 12/93