Fuel cleaner/additive for Onan generator

I am old so I still use Seafoam in my engine and genset. I disconnect the line from the main fuel tank and add 8 ounces of Seafoam in a gallon of gas and run the genset under load (2 A/C's running) it is also a good way to see how much gas your genset burns in a hr. Also I add some to the crank case before I change my oil in the genset. I was amazed at how much caked carbon came out of the crank case the first time I tried it. I do this about every 4 or 5 years. The generator runs very smooth after treatment. The genset is 24 years old and never had the carb rebuilt or any work on the engine it self. I not sure why people run it dry before winter storage if you exercise it once a month under load per Mfg instructions.