Fuel gunge attractor?

[vyv_cox]

The Kubota 2203 (50 HP Beta) is, according to my workshop manual, a Bosch injector pump with metered quantity of fuel distributed to each injector, so the spillage from the individual injectors themselves is likely to be tiny. But the injector and metering pump works, according to this source http://www.cs.rochester.edu/~jag/vw/engine/fi/injpump.html as follows:

The cam disk is rigidly attached to the plunger. The drive shaft rotates the cam disk. The cam disk rides on four rollers (only one shown in this picture), and has four lobes. Thus for each revolution the plunger will pump four times. Note that with this arrangement the plunger stroke is constant. The metering (regulation of how much fuel is delivered) is done not by changing the mechanical stroke, but by spilling some of the fuel through spill ports, and thus changing the effective stroke . This is done by uncovering a spill port under the control sleeve at a particular angle of rotation. The other purpose of the rotation is to deliver the fuel to the correct cylinder. This is done by having four four delivery valves (only one shown in the figure), one for every 90 degrees of rotation. During a full revolution the plunger makes four strokes, one at 0, 90, 180 and 270 degrees. During each stroke the delivery port in the middle of the plunger is connected to a particular delivery valve.
...
When the desired amount of fuel has been injected the spill port opens (located under the control sleeve in the figure), and the pressure quickly drops. This causes the delivery valve to close. During the rest of the stroke fuel is "spilled" through the spill port instead of being injected into the cylinder.

Thanks for that one. As far as I can understand it the spill valve is only internal and no fuel is returned to the tank. This suggests that the relatively large flow rates associated with some types of arrangements is not true here?

 

[RobbieW]

... Do you know how it is piped, particularly whether there is a return from the injection pump to the tank? ...

Boat in Sicily, me in Southampton. A quick search of an online parts catalog shows that the return pipe runs from the injector pump through each injector before returning fuel to the tank. There are point to point pipes for each injector for fuel delivery from the pump; its described as 'Indirect injection (E-TVCS)', the acronym seems to be a Kubota thing.