Besides gasoline coagulating in the carburetor of a standby generator causing failure, the second most common cause of generator failure is not exercising the generator under load. Just running a gen set without loading the alternator (I don't know why it's called a generator other than it generates electricity) without applying a load does nothing. You have to load the alternator with a current drain to cause the brushes to excite the armature and clean any tarnish off the copper segments. That applies to a portable gen set or a standby unit like I have. My 25KW unit exercises itself, but every month I isolate the utility power and let the gen set assume the load. I always have my wife use the washer, the dryer and the oven and turn on all the lights to work the unit and remove tarnish from the segments.
I didn't know there was any U.S. Law that limited the amount of stored fuel or propane. I guess about every farmer would be a criminal. I have 1000 gallons of propane in storage in 2 tanks all the time, 150 gallons of regular unleaded and 1000 gallons of diesel.
I believe Hondax has 6000 gallons of propane.