I replaced a lot of 4-71 generator set installations with John Deere 4.5ltr turbo diesel powered Kohler gensets. Not a much more reliable engine than a two stroke Detroit on generator duty IMO. Just can't get parts like in days gone by. Sure wish I'd have been able to keep one or two. Unfortunately they were returned to depot and used for parts to keep others still in service operational till all were replaced, or spare quantities built up. They were backup sets in the national airspace so quite important. Never did work on the two valve variety; all "N" series heads and injectors. This "92" in the truck is the only one of those I've worked on. Ran a lot of them as maintenance routines, but never worked on one. When I retired there was several 92's still going in the system as they were not being replaced on that contract.
Same thing happened with the Continental, Hercules, White, Studebaker/Onan, Caterpillar, IH, and several other names/sets until replaced in the Kohler contract to bring all under current builds. Many sets had nothing wrong with them other than ready parts availability being problematic.
Now they have trained monkeys to do the maintenance work; all they have to know is how to call the problem in so a subcontractor can be dispatched to make any repairs.