DETROIT DIESEL
Engine Tune-Up
THROTTLE DELAY MECHANISM
The throttle delay mechanism is used to retard full-
fuel injection when the engine is accelerated. This
reduces exhaust smoke and also helps to improve fuel
economy.
The throttle delay mechanism (Fig. 2) is installed
between the No. 1 and No. 2 cylinders on three
cylinder engines, between the No. 2 and No. 3
cylinders on four cylinder engines, or between the
No. 1 and No. 2 cylinders on the right-bank cylinder
head of V-type engines. It consists of a special rocker
arm shaft bracket (which incorporates the throttle
d e l a y cylinder), a piston, throttle delay lever,
connecting link, oil supply plug, ball check valve and
U-bolt.
A yield lever and spring assembly replaces the
standard lever and pin assembly on the rear end of the
injector control tube on In-line engines (Fig. 3). A
yield lever replaces the standard operating lever in the
governor of the 6V-53 engine (Fig. 4).
Fig. 3 - Throttle Delay Yield Lever (In-Line
Engine)
Operation
Oil is supplied to a reservoir above the throttle delay
engine is accelerated, movement of the injector racks
cylinder through a special plug in the drilled oil
toward the full-fuel position is momentarily retarded
passage in the rocker arm shaft bracket (Fig. 2). As
while the piston expels the oil from the cylinder
the injector racks are moved toward the no-fuel
through a .016" orifice. To permit full accelerator
position, free movement of the throttle delay piston is
travel, regardless of the retarded injector rack position,
assured by air drawn into the cylinder through the ball
check valve. Further movement of the piston uncovers
a spring loaded yield lever or link assembly replaces
the standard operating lever connecting link to the
an opening which permits oil from the reservoir to
governor.
enter the cylinder and displace the air. When the
Fig. 2 - Throttle Delay Cylinder
Fig. 4 - Throttle Delay Yield Lever (6V Engine)
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