Well.... those are very fancy machines! When I did this work I was the machine.
Nice to see the injector out I hadn't taken mine out yet (no reason). Yeah we called those unit injectors. The nozzle, pintle, spring and pump are all in one "unit". You have to set the rack up just right when swapping them. There are special tools but if you have finer machine tools (calipers, micrometers) they can fit or you can make the jig you need. Those machines in the videos are like the machine in the TM for the multifuel. Only big shops doing this all day have them. Then there's the rest of us....
For field service we would take them out, decarbonize the end with a specific cleaner and soft brush, then check them in the tester for a spray pattern and leakdown test. You were the actuator: large lever on a pivot and your arm pulling it. If it failed the leakdown or spray pattern out it came and a new nozzle/pintle would go in then back on the tester. Those components are way too fine for any type of field service they get swapped for new. Once they passed (spray pattern, leak down) you inserted a volumetric cylinder under them, set the rack with another jig, started pumping away. So many pumps was so many cc's of fuel at such and such a rack setting. Failing this was tearing it down again and installing a new jerk pump (matched piston and sleeve). There were variations on this. Some bench setups had small fuel pumps to mimic the engine driven pump supply pressure. All the rebuild stations were as compact as they could be. There's no space for those big test machines in ship engine rooms. You carry as much spare as you can afford to (or the company will allow) but to a large extent you have to be fairly self sufficient. The above it's how I was taught and what I did.
I don't see any reason one can't do this at home BUT you're going to have to be a bit more dedicated than a multifuel (basically a simple tractor). Not as complicated as the new high pressure PWM (pulse width modulated) though. When those came along the small shops got left in the dust. Much more expensive test equipment and no work around. Could it be done? Sure. Just an exponential amount of more dedication in both time and money....
I'd be interested in the specs on these. Pressures, volumes, etc... May tackle it someday. Maybe.... so many projects and I'm not even retired yet....
