Injection Timing Test - Toro Workman 3000 Series Service Manual

Injection Timing Test

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 one 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 and spring. The valve seat
must remain in place.
B. Replace the valve holder and tighten it in place.
C. Connect the fuel injection pipe to the nozzle
holder so the open end of the pipe will discharge fuel
into a container.
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 one cylinder compression stroke
is approaching by checking the push rods. Both push
rods on the number one 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 fuel pump will
supply fuel through the injection pump and out the
number one injection pipe.
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 screwdriver inserted between the transmis­
sion drive hub and rubber coupler will provide control
and leverage to slowly rotate the engine crankshaft.)
NOTE: Wear of the internal parts in the injection pump
may allow the fuel to continue to drip from the injection
Workman 3300-D/4300-D
pipe. If the slowest flow rate exceeds 1 drop in 5
seconds, repair of the pump should be considered.
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 19
standard fuel injection timing. The outside marks repre ­
o
sent 21 BTDC and 17
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.)
1. Delivery valve holder
2. Holder stopper
3. O-ring
4. Delivery valve
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o
BTDC;
o
BTDC; the acceptable range of
o
. Increase shim thickness
Figure 20
5.Spring
6. Gasket
7. Valve seat
Figure 21
Liquid Cooled Diesel Engine