Vedeneyev M-14P, Maintenance Manual

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The reducing valve assembly comprises valve (6) with diaphragm (25) and spring (27) secured on it by
nut (1). Nut (1) is safetied with lock (2). One end of spring (27) thrusts against the valve stem seat and the other
end,against the end of adjustment screw (28).
The conical part of reducing valve (6) rests on the seat in reducing chamber housing (7), while its
cylindrical guide with two decompression flats enters a recess in the reducing chamber housing.
Gasoline pressure in the delivery space is adjusted by varying tension of spring (27) by adjustment screw
and adjustment screw head (30).
When rotating the head clockwise, adjustment screw (28) screws into the boss of cover (26) and
compresses spring (27). Fuel pressure rises. When the head is rotated counter-clockwise, the spring weakens
and the fuel pressure decreases.
The reducing valve cylindrical guide carries priming valve (23) serving to fill the fuel line before starting
the engine.
To prime the fuel line, gasoline is pumped through twelve drilled holes uniformly spaced around the
mushroom-type head of reducing valve (6). The priming valve is pressed to the end face of the reducing valve
mushroom-type head by spring (22), thus sealing off fuel supply.
The pump sealing arrangement comprises two rubber seals (17) with metal inserts, pressed in seal nut
(13).
The seal inner lip embraces shank (15). To additionally press the seals to the shank, spring (14) is
installed on the seal cone outer surface.
The outer surface of the pumping unit is sealed with rubber sealing ring (10) which is lodged in the recess
of upper bearing (18).
Rubber ring (11) precludes leakage of oil along the thread of seal nut (13).
Seeping fluid is drained from the drain space via special passages in the seal nut which connect the drain
space with drain connection (42).
The seal nut is safetied with retaining ring (16).
The joint between the pump housing and the reducing chamber housing is sealed by paronlte gasket (8).
3. OPERATION
The pumping unit operates on the principle of varying the volumes of the sleeve internal space during
rotation of eccentric rotor (20) (Ref. Pig* 1) with vanes (37)«