Injection Pump Servicing - Toro Groundsmaster 300 Series Service Manual

Injection Pump Servicing (Fig. 41)
A built-in three-cylinder injection pump is mounted
on the right-hand side of the cylinder block. It
consists of a pump element (plunger and barrel assem-
bly), a delivery valve, a tappet and a smoke set unit. As
the pump cam rotates, the plunger is moved up and
down through a prescribed stroke, delivering fuel to the
engine cylinders. A key operated stop system is pro-
vided.
Fuel Injection Control
The fuel injection rate is controlled by changing the
effective stroke of the plunger within the barrel. The
plunger is rotated by the control pinion which meshes
with the plunger lower collar to directly turn the plunger.
As the engine turns, the injection pump camshaft rotates
to move the control rack by way of the governor weights,
governor sleeve, and lever. The control rack slides to
turn the control pinions. Movement of the control rack to
the right decreases the fuel injection rate and movement
to the left increases the rate.
Fuel System Service
1. Air vent screw
2. Stopper
3. Control rack
4. Return spring
5. Gasket
6. O-ring
7. Plunger
8. Lower seat
9. Tappet
10. Valve holder
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Figure 41
11. Spring
12. Delivery valve
13. Valve seat
14. Plunger barrel
15. Adjusting plate
16. Control pinion
17. Upper seat
18. Plunger spring
19. Pump housing
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Groundsmaster 300 Series