3208 – Heavy Sleeve Metering Fuel System (HSMFS)

Heavy Sleeve Metering Fuel System (HSMFS) Fuel Flow Schematic
(1) Fuel priming pump (closed position). (2) Fuel priming pump (open position). (3) Return line for pressure relief. (4) Pressure relief to pump inlet. (5) Fuel injection nozzle. (6) Fuel tank. (7) Check valve. (8) Check valve. (9) Check valve. (10) Fuel bypass valve (with purge orifice). (11) Fuel inlet line. (12) Water separator. (13) Fuel filter. (14) Fuel line (to fuel injection pump). (15) Fuel transfer pump. (16) Camshaft. (17) Fuel injection pump housing.

Fuel from fuel tank (6) is pulled by fuel transfer pump (15) through water separator (12) (if so equipped) and fuel filter (13). From fuel filter (13) the fuel goes to fuel injection pump housing (17). The fuel goes in the fuel injection pump housing (17) at the top and goes through an inside passage to fuel transfer pump (15). Fuel under pressure fills the fuel injection pump housing (17). Fuel injection pump housing pressure is controlled by fuel bypass valve (10).

Pressure of the fuel at Full Load is 255 ± 48 kPa (37 ± 7 psi). If the fuel pressure in the fuel injection pump housing (17) gets too high, fuel bypass valve (10) will move (open) to let some of the fuel return to the fuel tank (6). If return line for pressure relief (3) should become blocked the pressure relief to pump inlet (4) will open at 360 ± 70 kPa (52 ± 10 psi). This pressure relief to pump inlet (4) is intended to provide return to tank capabilities, but lip seals life will be shortened.

Flow Of Fuel Using The Priming Pump (HSMFS)
When the handle of fuel priming pump (2) is pulled out, negative air pressure in fuel priming pump (2) opens check valve (7) and pulls fuel from fuel tank (6). Pushing the handle in closes check valve (7) and opens check valve (8). This pushes air and/or fuel into the fuel injection pump housing (17) through the fuel passages and check valve (9). Air trapped in the fuel injection pump gallery will vent to tank through fuel bypass valve (10). More operation of fuel priming pump (2) will pull fuel from fuel tank (6) until the fuel lines, fuel filter (13) and fuel injection pump housing (17) are full of fuel. Do this until the flow of fuel from fuel bypass valve (10) is free of air bubbles.

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