Injection Timing Test - Toro Groundsmaster 300 Series Service Manual

Injection Timing Test (Fig. 20, 21)
Injection timing can be adjusted by installing shims
under the pump body. The timing is important because
it determines when the fuel enters the combustion
chamber.
The most accurate method of timing is done with an
electronic diesel timing tester (available from major tool
supply companies).
The following method is an initial setting for starting the
machine.
1. Remove the number one injection pipe from both the
pump and nozzle. (The number 1 cylinder is opposite
from the flywheel end of the engine.)
2. Set up the injection pump for the test:
A. Remove the delivery valve holder (Fig. 20). Re-
move the delivery valve assembly and spring.
B. Replace the valve holder and tighten it in place.
3. Put the throttle control in the middle of its range of
travel.
4. Slowly rotate the crankshaft counterclockwise from
the flywheel end (normal rotation) until the IT marks
(injection timing marks) on the crankshaft pulley are
approximately 1/2 in. (21 mm) from alignment with the
stationary pointer on the engine gear case (Fig. 21).
Make sure the number 1 cylinder compression stroke is
approaching by checking the push rods. Both push rods
on the number 1 cylinder should be loose and the valves
closed. If either push rod is tight, rotate the engine
crankshaft one full revolution and inspect the push rods
again.
5. Turn the ignition switch ON so the electric fuel pump
will supply fuel through the injection pump and out the
number 1 delivery valve holder.
6. Rotate the engine crankshaft SLOWLY in the normal
direction until the flow from the number one injection
pipe just stops. This is the moment of actual injection
timing. (A large screwdriver inserted between the trans-
mission drive hub and rubber coupler will provide control
and leverage to slowly rotate the engine crankshaft.)
®
Groundsmaster 300 Series
7. Standard injection timing can be confirmed by the IT
marks on the crankshaft pulley and the stationary
pointer on the crankcase (Fig. 21).
The center mark on the pulley represents 23
standard fuel injection timing. The outside marks repre-
o
sent 25 BTDC and 21
injection timing.
Shims are available in different sizes from 0.2 to 1.0 mm
thick. Adding or removing a shim, 0.1 mm thick, will
change injection timing by 1
if injection is too early. Decrease shim thickness if
injection is too late. (See Injection Pump Service in the
Fuel System Repairs section of this chapter.)
Removing the delivery valve
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o
o
BTDC; the acceptable range of
o
. Increase shim thickness
Figure 20
Figure 21
Testing
BTDC;