buying new gen set is better option buy branded one like Elemax , Honda, or Yamaha. all of these are nice machines,
but buy it directly from company not from their dealers, most of the dealers have chines replica of all these brands looks same and there is no difference,but they are substandard products so don't be cheated by any of such thing. buy it straight from there office you can find there address on there webs.
new genrator comes with all importanat thing specially owner manaul read it throughly its important, and maintain it by book
normaly on bigger generators like above 500kva, if it is installed in important place where power failer is unnegociatable, we have a log book we have to maintain it by that book every thing is written in it its like a chart and we have to write each and every job in it.on the other hand operator also have to log the working hours and all the readings of the gauges. during running. we also comment on its conditions like about the remaning hours of that engine its normal procedure through out the world.
you even find this chart in your generator owner manaul.maintain it as per book and change the oil after every 50 hour (if there is no oil filter in your generator) dont foget to initial run the generator without load for few hours because new gen set needs initial running. in this time engine gets over heat due to high friction in newely fitted parts with in few hours the friction will disaappear and engine gets smooth and stops over heating too. now starts putting the load. smoothley never put the complete load on gen set at once and let them maintain normal working temprature for 4 to 5 minutes . care full about a/c and refrigrators wait for at least 10 to 15 minutes before starting these things . otherwise both you gen set and your refrigrator will start making troubles and this thing will even distroy the avr or winding of your gen set.
while you are shopping for new gen set don't relay on the written rating they are always fooling specialy in chines set, there are lot of differance say like 2.5 kva chines are nothing more than normal 1.4 to 1.8 kva. In branded like in honda , yamaha and in elemax its always torq load (means this set has a few second load capacity of 3kva or what ever the rating is ) this thing is also mentioned in its inital pages of owner manaul, as per my own experiance if you run your gen set under 50% load it gives you the longest life span on each and every parts.so buy gen set with 50% plus capacity of your required load if you wana run 1000watt load buy 2.5 kva set if you have 3kva load buy 6.5 kva in this example .5kva is torq actual output of gen set is 2 kva and you are running it well under like 1kva load it will give you best time ever. i have a example of elemax 2.8 kva with 12000plus hours now and still running i will overhaul this set in upcomming winter.
you have enough buget to buy 2.5 kva or 3 kva set dont go for ATS, the abrupt overloading will damage your set you need a lot more bigger set like above 10 or 15 kva set which have enough safety devices on board with water cooled engine all the above mention things are my personnel experiance go to yahoo or google check them and then apply.
hope your new gen will serve you long.feel free to ask any question