well my 2 cents worth, on detroits
(having been certified by detroit for 53,71 and 92 series in 1978, and having built, rebuilt hundreds of them)
the 2-71 at 1200 rpm won't be nearly as bad as one at 2100 and full load, but it will still be several times louder than any lister big or small.
they would be a bear to tame in a residential area, can it be done, probably but at a considerable expense of time and effort.
aside from that, the engines are designed to run for a very long time, and parts will likely always be available.
also it is fair to note that the detroit has probably twice the working parts of anyother diesel engine, and likely 10 times the working parts of a lister!
the cylinder head alone probably has a hundred parts, including all the hex plugs. the govenors are finicky to get setup right, you will learn all about air gaps if you
mess with them at all, get it wrong and no power. the air gap is around 1.5 thousands at 1100rpm iirc.
blowers are almost a science all unto their own, and i would not recommend anyone try and do one himself. spec tooling here
even installing liners, and pistons take special tools to do it right, do it wrong and it uses oil.
the airbox has drain tubes, and the detroit will vent not only air but partially unburned fuel and oil, makes a mess. dont even think about plugging them, that is asking for a runaway
engine.
i probably would not recommend one to anyone that is not versed in detroit 2 strokes, and qualified mechanics are few and far between unless you live around
marine application. the rest of the country detroit mechanics have faded away, as the last 92 series was installed in trucks back in the mid 80's the 71 series predates that.
i have seen them, and have been tempted to get one too. but i am not anticipating more than a 2 hour run per day, out in the country, and i have extensive experience with these engines. if it werent for these factors i wouldnt even think about it.
if one accepts a lister to be butt simple, the detroit is its evil alter ego
bob g