I appreciate you straightening me out out but you sure didn't make me feel too smart!
Well - you don't need to be too worried.... I took an LD apart a couple of years ago, to try to fix a hard starting problem (it needed spinning almost up to operating RPM to fire), and now I haven't got a flippin' clue how to put it back together again! And that's just ONE cylinder!
Anyway - it's not about being smart, it's about having the knowledge in the first place. I've been messing around with mechanically injected diesels of one form or another for 20+ years, so I know what I'm looking for. Still doesn't help me put the buggers back together afterwards! One of the main reasons I've never stripped down my working CS!
Anyhooo - some more knowledge: There should be two pipes on each injector. The bottom one is the HP feed in, which when the injection pump gets a smack from the cam, pushes a very high pressure pulse into the injector, causing it (hopefully!) to inject. Any unused fuel which didn't make it out of the nozzle, is returned - usually to the tank, but (especially on little engines like these) sometimes to a catch can or - if you're unlucky (e.g. CS engine with no return pipe) to a place where spare fuel can wash out the rocker grease into the engine causing umpteen problems if not spotted early enough. I don't see any return pipes, but maybe I'm not looking hard enough. They are semi-optional: A good idea, but if the surplus fuel just runs away down the side of the engine, they shouldn't cause any operating problems. Environmental, well, different story...
Anyway, you say it runs & produces power, which suggests you don't have any pressing problems with your fuel system. To fully bleed any air out you'd loosen the nut on the back of the injector & crank the engine until it spits just fuel & no air. Then repeat 4-5 times because there's always a sodding bubble trapped somewhere!