Step #1 is a compression test.-----Post your numbers.-----Next is a spark test.-----Does spark jump a gap of 3/8" on all leads ?-----I chuckle when I read ----" rebuilt the carburetors , motor still runs the same ".
Use a proper spark testing device.---Easy to make with wire and piece of wood , stick , tape at home.----Spark on a good system should jump a gap of 3/8" or more.
There may be more things wrong with this engine.-----Post the compression test numbers.-----Any other trouble shooting done ?-----Water pump impeller changed recently or never ?-----Checked for water in the fuel ?----Flywheel key checked ?-----Might be running on just 1 cylinder !
You might want to run with a 50:1 mix in your fuel tank.-----Mark oil tank.----Then calculate how much oil is being injected.----Or have a shop run a test on oil injection system.
Need to tear engine down.------Inspect cylinder for cracks.----Determine reason for the failure.-----Then do the repairs.----Inspect all other cylinders too.-----Clean carburetors.----Inspect oil injection bits if that system is in service.
Those compression numbers are not good.-----Remove bypass covers and inspect pistons and rings.-----Do a complete evaluation before you spend any beer tokens on these.----Agreed you need the belts for the generators .----Generators must work.-----You need all the controls and junction boxes too.
