DR4Film
The Onan LP generators do burn propane in its vapor form.
The liquid propane flows from the tank to the generator where it is vaporized by a VAPORIZER, (aka: propane carburetor), on the generator.
BTW the 'vaporizer' is warmed by the heat of the running generator engine ... preventing freeze ups (even in temps as low as -40 degrees Celsius .
Heard from a kid in the multi family campsite in a Michigan campground: "Look the rich lady is sweeping off the picnic table".
Reply from many adults: "SHUSH".
IMO Goodyear G159 tires are not a current concern/worry/danger ... because:
Goodyear G159 tires where only manufactured 1996-2003.
Every one was at least 10 years old in 2013 ... (and had therefore AGED OUT 8 years ago).
FishAR
Most use a single 2 stage regulator: https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.rvupgradestore.com%2F2-Stage-Propane-Regulator-Horizontal-p%2F06-0381.htm&psig=AOvVaw1JH_WbfaxEsKNszP-8ShZN&ust=1628960703237000&source=images&cd=vfe&ved=0CAoQjRxqFwoTCNjojNS9rvICFQAAAAAdAAAAABAFs
As of January, 2021, Allison recommends only TES 668 approved. ATF for On-Highway use.
See: https://www.allisontransmission.com/docs/default-source/aftermarket-brochures/sa8742en-tes668-brochure_f_rev.pdf?sfvrsn=2189e81d_0
And:
https://www.allisontransmission.com/parts-service/approved-fluids/on-highway-fluids
IMPORTANT NOTICE:
Valvoline MaxLife synthetic ATF is NOT a "TES 295 Approved transmission fluid".
However Valvoline SynGard synthetic ATF is TES 295 approved ... as are the 13 others listed here: https://allisontransmission.com/parts-service/approved-fluids/on-highway-fluids?fbclid=IwAR22Gs6sntKnu7KI8hm_ZZuzfh-mD2c2mLK7zMNhjS-BPWFd0w_aOsZxvNg
Granville Barker
Methinks that's because most available propane fueled appliances/accessories, (BBQ grilles, space heaters, lanterns, etc.), have a built in pressure regulator .... requiring them to have 'full tank pressure propane' to burn/operate correctly.