Governor Servo

TM-5-3805-263-14P-2 Grader Heavy Road Motorized Type I Nonsectionalized Type II Sectionalized Manual
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FUEL SYSTEM TM 5-3805-263-14&P-2 The force of governor spring (1) always pushes to give more fuel to the engine. The centrifugal (rotat- ing) force of flyweights (8) always push to get a reduction of fuel to the engine. When these two forces are in balance (equal), the engine runs at a constant rpm. When the engine is started and the governor is at the low idle position, over fueling spring (9) moves the riser forward and gives an extra amount of fuel to the engine. When the engine has started and begins to run, the flyweight force becomes greater than the force of the over fueling spring. The riser moves to the rear and reduces the amount of fuel to the low idle requirement of the engine. When the governor control lever is moved to the high idle position, governor spring (1) is put in compression and pushes riser (10) toward the flyweights. When the riser moves forward, lever (7) moves sleeve (2) and valve (3) toward the rear. Valve (3) stops oil flow through governor servo (5) and the oil pressure moves piston (4) and the fuel rack to the rear. This increases the amount of fuel to the engine. As engine speed increases, the flyweight force in- creases and moves the riser toward the governor spring. When the riser moves to the rear, lever (7) moves sleeve (2) and valve (3) forward. Valve (3) now directs oil pressure to the rear of piston (4) and SYSTEMS OPERATION moves the piston and fuel rack forward. This de- creases the amount of fuel to the engine. When the flyweight force and the governor spring force become equal, the engine speed is constant and the engine runs at high idle rpm. High idle rpm is adjusted by the high idle adjustment screw. The adjustment screw limits the amount of compression of the gover- nor spring. With the engine at high idle, when the load is increased, engine speed will decrease. Flyweights (8) move in and governor spring (1) pushes riser (10) forward and increases the amount of fuel to the engine. As the load is increased more, governor spring (1) pushes riser (10) farther forward. Spring seat (11) pulls on stop bolt (12). Stop collar (15) on the opposite end has power setting screw (14) that controls the maximum amount of fuel rack travel. The power setting screw moves forward and makes contact with load stop bar (13). This is the full load balance point. Governor Servo The governor servo gives hydraulic assistance to the mechanical governor force to move the fuel rack. The governor servo has cylinder (3), cylinder sleeve (4). piston (2) and valve (1). When the governor moves in the FUEL ON direc- tion, valve (1) moves to the left. The valve opens oil outlet (B) and closes oil passage (D). Pressure oil from oil inlet (A) pushes piston (2) and fuel rack (5) to the left. Oil behind the piston goes through oil passage (C), along valve (1) and out oil outlet (B). 1-10

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