I too only start the drive engine when I will drive the MH for at least 1 hr. The Onan genset manual
states 2 hrs once a month.
During cold weather, if we're home, I plug in 2 electric space heaters(not same circuit) to load the genset and heat the interior while working on something in the MH.
That said, our MH had been parked in a barn for 6 years when we purchased it, with no apparent damage to either power unit.
2000 Winnebago Ultimate Freedom USQ40JD
, ISC 8.3 Cummins 350, Spartan MM Chassis. USA 1SG, retired;PPA,Good Sam Life member,FMCA."We the people are the rightful masters of both the Congress and the Courts - not to overthrow the Constitution but to overthrow men who pervert the Constitution. "Abraham Lincoln"