earlwb

I would think that it is just the opposite. The straight ether and oil is much more harsh on the engines than using fuel with kerosene in it. The first model engines actually oval-ed out the crank bushing with lots of usage. All that ether tends to burn very fast like a explosive does.

The problem with the modern fuels is oil content. You need to add more oil to it. But I see your point though. it is something to think about. I was watching my engines closely to ensure they weren't running too hot or getting pre-ignition going too. Thus when I ran them, fixed compression, they tended to be a little bit on the undercompressed side. But in any case your concerns are duly noted.