Here is a 1941 military "M-3" 3 phase 120 volt AC machine with a 4 cylender Hercules enging.  I found this one about half buried in a hill-with trees growing through it.  It wasnt seized, so I gave $25 for it.  About 10 work on the carburator had it running well.  I got 6 years of so of good service out of it-and gave it to a neigbor-who used it a bunch for a while-now its got a bit of a rod knock-probably and easy fix.

This one is my newest (most recently aquired) gas engine-dont know the year yet, but its an old throttle governed International Harvester gas/kerosene enging.  It runs well-seems to need nothing, except maybe some paint-and some work to do!  It will probably wind up pushing electrons through batteries or something.  At this point-all it does is spin-which is also enjoyable!

Here is a very old 120 VAC machine I dug out of a pile.  Its an old Briggs and Stratton engine.  It came seized up tight. I poured about 1 quart of water out of the crank case, filled it back up with oil.   I took the head off-soaked it in WD-40 for about 10 min-and beat the piston down with a sledge hammer-took about an hour of pounding on the piston and flywheel before I felt confident enough to throw the head back on and start it.  Took only 2 pulls before it started running-took about 10 minutes for the brushes to clean the commutator off enough for it to generate.  It's probably only about 500 watts or less.