As far as I know, there was never a schematic produced which dealt with the cold start mechanism on the 2000 series engines. The only thing you can do is check the parts book. Because the throttle and stop lever shafts are supported by the housing cover, it is difficult it see what is actually happening in there without cutting a large hole in the cover....( and that has been done before).
Basically the position of the fuel
rack or control rod is controlled by the governor linkage and spring pressure applied by the throttle cable. At full throttle the linkage comes up against the max throttle stop, but when the the cold start is engaged, the stop is moved aside and that allows the linkage to move further than normal. This allows more fuel than normal to be injected, and if I recall
correctly it also retards the injection timing so that injection occurs closer to TDC.
You can tell if your cold start mechanism is working by trying the following:
Remove the 30 mm hex head plug
on the rear surface of the block just to the rear of the last injection pump. Take care not to loose the washer under the plug
. When this plug is removed you will see the aft end of the injection pump rack/control rod. With the throttle at idle, activate the stop lever, and the end of the rack will move aft and protrude about 4 mm past the surface of the block. Releasing the stop lever will allow the rack to move back into the block and it should reside about 4 or 5 mm ahead of the block surface. Now, put the throttle at its maximum RPM
position and hold it there and then pull the stop lever all the way out and then push it back in again. When you do this stop lever movement, the fuel rack should move forward from its normal position until it is about 10 -12 mm ahead of the block surface. This is the cold start position.
If you get movements similar to these, your cold start is functioning correctly. You might find it easier to disconnect the throttle and stop cables
from their attachment points on the engine in order to make it easier for one person to manipulate things and get full travel of the levers.
If you need a PDF of the parts book page, send me a PM and I will send it to you.