Thanks to you both. What does it entail to purge the pump and injectors? My manual does not explain things very well, i.e., in the manner in which, I as one who has never worked on a diesel before, feels comfortable to start stripping things. Is it a matter of opening the cover and start pulling apart? Can I take this chance?
Hope you don't mind, this reply was in the wrong place, so I moved it for you....
To answer the question, although I'm not familiar with the SR2, I can't believe it's much different to Lister's other engines... basically, pull the rocker cover off & you should see the top of the injector, with 2 pipes (ideally!) - a feed pipe, and a leak-off pipe. The latter returns to the fuel tank usually, and carries off any fuel that wasn't injected.
To bleed the system, simply loosen the nut holding the inlet pipe, and maybe back it off a few turns. Or if you're feeling brave (and don't mind getting your hands covered in diesel) you can pop the pipe all the way off. Now crank the engine over (or run it, if you don't mind making a mess). You should see a nice healthy spurt of diesel out of the pipe every time it injects. With the pipe just loosened, any air should seep out (often blowing bubbles), when it all goes quiet and liquidy, tighten the pipe back up. Repeat this process for the second cylinder.
That's the fuel system completely bled, so if that doesn't fix your issue, next stop is to pop the injectors out... This is also fairly simple, usually...
1) Undo the fuel lines to the injectors and move them out of the way.
2) Undo the bolts holding the first injector. See if it'll pull out.... if not...
2a) Put the injector bolts back in, but leave about 1/16th" slack between bolt head and injector flange.
2b) Spin the engine over until the compression pops the injector out.
SEE WARNING BELOW 2c) Remove bolts and injector (it should come out once unstuck from its seat).
3) Repeat for 2nd injector.
4) Now your injectors are out, turn them upside down and re-connect the inlet fuel line. Ignore the leak-off (this is going to make a mess anyway...)
5) Now turn the engine over by hand, or on the starter. Observe spray patterns from injectors. As per Mike's post... don't put anything (hand, eye, etc.) near the spray, it does have enough power to penetrate the skin!! And if you stick your eye over it, well, just don't do it, OK. Note that you need to turn the engine fast enough that the injctor gets a proper pulse of fuel; if you just roll it over the injection event, it'll just dribble. If that.
6) To re-assemble, just undo the fuel lines, carefully push the injectors back down their holes, bolt up nice and tight, re-connect fuel lines, job done.
WARNING! - Never EVER start (or even rapidly turn over) a diesel engine with the injector unbolted and the bolts removed! The compression can (and WILL) cause the injector to be fired out of the engine block, straight through you, clean across the yard, and it WILL kill or seriously injure the neighbours cat/child/wife (or all three) - so even if you survive, you'll be sued into oblivion by the trail of carnage left behind. YOU HAVE BEEN WARNED!
That said, sometimes, the only way to remove a stuck injector, is to run the engine hard with the injector fastinings loosened. And, sometimes, even that doesn't work... I went to replace the injectors on my old bus, of the 6 we got 5 done, the 6th will NOT move. Loosened the bolts, drove it 500 miles, and it STILL won't come out...