Unregulated voltage gens start at a high voltage and usualy reach 120
60 hz at load. Start voltage is usualy around 135, but cheap low powered
units easily swing 35 v ++. Even Coleman in their manual says if
electronics are to be used buy a separate regulator and they even give
you a telephone #.
Those regulators can double cheap generators cost. Regulated units
usualy swing only 10- 15v.
Honda has a line of " clean power" stable signwave generators that are
as clean or cleaner than your utility co. And they have a line that is
voltage regulated. And are very quiet in sound noise.
Whatever you get test it before you need it to full load with a meter
to be sure it will do what you need. You should look for voltage
regulation and find out the % volt swing the unit is desiged for and see
if your equipment can handle it. HZ varies with voltage , many motors
wont start if Hz is off. Look for a good motor with steel sleeve and
pressure oiled. The cheapest unit that does this is a Generac 4000exl
for 700 at HD it also has electric start and an oil filter, but it stil
swings apx 10v. For better go Honda , their inverter line is the best
but at 2.5 x the price of Generac. Some Colemans use techumpsee motors
some models which only last 350 hrs Pressure oiled steel sleeve can go
3500 hrs.
With generators you really get what you pay for