Toro Groundsmaster 328-D, Service Manual

Page: 68 / 402

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.
Figure 41
1. Air vent screw 11. Spring
2. Stopper 12. Delivery valve
3. Control rack 13. Valve seat
4. Return spring 14. Plunger barrel
5. Gasket 15. Adjusting plate
6. O-ring 16. Control pinion
7. Plunger 17. Upper seat
8. Lower seat 18. Plunger spring
9. Tappet 19. Pump housing
10. Valve holder
Fuel System Service Page 4 - 38 Groundsmaster
®
300 Series