Personally I would want to know which firm overhauled it and to know how much confidence I could have in them. That would guide me as to what to be careful about. However, if I didn't know which firm it was then I would be careful about making sure the bearings and cylinder clearances were not so tight as to cause seizure or wiping when initially run.
Check the coolant - is it of the anti-corrosion type or plain water? Preferably put the anti-corrosive in and make sure you have the anti-freeze solution correct as well if running in low temperature zones.
Make sure the coolant level is correct: squeeze the flexible hoses, try to get any air out of the system.
Check the condition of the coolant hoses and clamps - you don't want any of these blowing off causing rapid overheating. Check the clamps are tight enough.
Check the radiator is clear/clean and that the fan has been mounted the right way - most static generators (if I recall correctly) blow the air outwards through the radiator - the opposite of what happens on vehicles.
If housed in a room, make sure the room is well vented so that hot air escapes easily and cold air enters easily.
Check the oil, air and fuel filters have been changed and make sure there is adequate suitable quality oil in the sump.
If the engine has not yet been run then remove the filter if a canister type and fill it with oil and replace it back on (make sure it is a new filter that you are doing this to).
If you can remove the rocker/cam cover, do so and liberally coat the cam or rocker rack with oil and replace the rocker/cam cover.
Make sure there is not too much oil in the sump now! Turn the engine over by hand - with power off - check the engine is not too tight. You will probably need to use a socket and ratchet but should be able to turn it over with a short 10 or 12 inch ratchet.
Make sure that you can turn the engine off before you start it - there should be a fuel cut off device electrically operated - make sure this cutoff device works so that you can stop it when you need to. If all else fails you can block off the air flow to stop it but watch you don't suck something into the engine when doing this.
Make sure the oil pressure lamp is lighting up when ignition is on.
If there is an oil pressure gauge
If coupled to the generator/alternator ensure it is not connected to any electrical load when first testing the engine and that there is no danger of any loose wires/sloppy connections causing short circuits leading to damage or a fire.
Check that the diesel injection pipes are not rubbing/chafing on anything.
Check that the fuel filter has been changed.
Check that the ... (more)
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