3-146. FUEL FILTER, FUEL STRAINER, FUEL LINES AND MANIFOLD
CONNECTIONS - MAINTENANCE INSTRUCTIONS.
(1) A fuel strainer (primary) and fuel filter (secondary), are used to remove impurities from the fuel. The
fuel strainer is located between the fuel tank and the fuel pump. The replaceable density-type
element is capable of filtering out particles of 30 microns (a micron is approximately .00004 inch).
The fuel filter is installed between the fuel pump and the fuel inlet manifold. The replaceable paper-
type element can remove particles as small as 10 microns.
(2) The fuel strainer and fuel filter are essentially the same in construction and operation.
(3) The filter and strainer consist basically of a shell, a cover and a replaceable filtering element. The
assembly is made oil tight by a shell gasket, a cover nut or bolt, and a cover nut or bolt gasket.
(4) The central stud is a permanent par of the shell and, when the unit is assembled, extends up
through the cover where the nut or bolt holds the assembly together.
(5) A filter element sets over the central stud inside the shell and is centered in the shell by the stud.
(1) Since the fuel strainer is between the fuel supply tank and the fuel pump, it functions under suction.
The fuel filter, placed between the fuel pump and the fuel inlet manifold in the cylinder head,
operates under pressure. Fuel enters through the inlet passage in the cover and into the shell
surrounding the filter element. Pressure or suction created by the pump causes the fuel to flow
through the filter element where dirt particles are removed. Clean fuel flows to the interior of the
filter element, up through the central passage in the cover and into the outlet passage, then to the
fuel inlet manifold in the cylinder head.
(2) The following paragraphs contain the maintenance instructions:
Fuel Lines and Manifold Connections