I've had a few conversations with some pros. One, the Maine Snowmobile Association rep. He said the alcohol is a great solvent and cleaner, in an older machine, run only on traditional gasoline, the tank is lined with varnish. The ethanol proceeds to remove the gunk and deposit it in your filter...or carb. And it also eats rubber parts that are not formulated for it.
He also said the snowmobiles that did blow up, would have anyway, because the operators are out on frozen lakes wide open for long periods, over 100 MPH....things can break.
if you didn’t have vented caps, then your carbs would starve for gas eventually.
I suppose you could get, or make some sealed caps and instead of running the tank dry, just replace the vented cap on a partial tank of fuel. (when you put the machine to bed)
After I run out gas from my machines for the winter, I leave the cap off. Seems to work okay for me. I’ve had much less rebuild time since doing that. But your discussions with the rep are something to consider. I’ll have to think about old varnish and potential new varnish and all that. Thanks,