Engine Tune-Up
THROTTLE DELAY MECHANISM
Fig. 3 - Throttle Delay Cylinder and Yield Link
The throttle delay mechanism is used to retard full
Inspection
fuel injection when the engine is accelerated. This
When inspecting the throttle delav hydraulic cylinder
reduces exhaust smoke and also helps to improve fuel
it is important that the check valve be inspected for
economy.
wear. Replace the check valve if necessary.
The throttle delay mechanism (Fig. 3) is installed
To inspect the check valve, fill the throttle delay
between the No. 1 and No. 2 cylinders on the right-
cylinder with diesel fuel oil and watch for check valve
hank cylinder head. It consists of a special rocker arm
leakage while moving the engine throttle from the idle
shaft bracket (which incorporates the throttle delay
position to the full fuel position
cylinder), a piston, throttle delay lever, connecting
link, orifice plug. hall check valve and U-bolt.
A yield link replaces the standard operating lever
connecting link in the governor.
Operation
Oil is supplied to a reservoir above the throttle delay
cylinder through an orifice plug in the drilled oil
passage in the rocker arm shaft bracket (Fig. 3). As
the injector racks are moved toward the no-fuel
position, free movement of the throttle delay piston is
assured by air drawn into the cylinder through the ball
check valve. Further movement of the piston uncovers
an opening which permits oil from the reservoir to
enter the cylinder and displace the air. When the
engine is accelerated, movement of the injector racks
toward the full-fuel position is momentarily) retarded
while the piston expels the oil from the cylinder
through an orifice. To permit full accelerator travel,
regardless of the retarded injector rack position, a
spring loaded yield link replaces the standard
operating lever connecting link in the governor.
Fig. 4 - Adjusting Throttle Delay Cylinder
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