Derek.
I have seen these advertised, particularly in the USA where gas is quite cheap (but they still have cheap petrol too)
To me, the problem would be that gas (lpg) has a very insidious habit of leaking, then accumulating in the most unexpected places. (heavier than air)
Whilst living on the central coast for nearly 10 yrs. there would have been that many boats blown out of the water by a small gas leak accumulating in the bilge then going boom when the engine starter motor ignited it.
At least petrol does not have the same propensity to leak, and when it does evaporation of its lighter fraction carries it away.
Purely an aside, I recently bought the small Honda eu10i generator as an auxilliary supplement to our normal camping power requirements.
Without wishing to advertise it, its quietness in running is remarkable.
cheers mikel

I have a 2kva generator running of a 5hp robin 4stroke that runs on LPG, I bought it second hand a few years ago for a couple hundred bucks, but i don't like it as you need a 9 kilo bottle, you never know when it's going to run out, with a petrol model you can check it & top it up anytime.
Dont get me wrong it's quiet runs clean, starts easy, but for my purposes, it is a pain going 5kays to the closest town for gas, & they don't always have it, so then it's 80kays to the closest main town.
We always have jerry's of petrol laying around for the chainsaws, motorbikes, paddock bashers, etc
Thats the same reason i use our tilly more than the gas light, i can leave a 20litre drum of kero there all year round.
While on the subject it has started playing up lately, it will drop to 50v after a few hrs, you let it cool down & she's right again, it has a huge regulator come earth leakedge box on it i recken thats the problem any idea's where to get it looked at in sydney.


Cheers
Trev
Aus

I bought it because it was belt driven & i knew i could fit any engine to it.
I have another 5hp robin petrol motor & a 5hp Ozzie takumsi (something like that) i was going to make a new frame with out the gas blower.
It will be petrol & a lot lighter, i was also going to gear it up a bit so the engine isn't reving so hard.
I will get around to it one day, i have to get someone to check out the regulator (earth leakedge) first.
Unless someone wants to by it
Trev
Aus