What's the difference between marine gas vs "regular" gas?
Do you mean gas/oil mixed for 2 stroke engines like weed whackers, chain saws etc?

I looked around a bit outside GW on the subject. Seems a lot of marine gas is ethanol-free, but not all. Some said it depends on which state you were at.

I was unable to find out what the ethanol % was at my local BP station! No notice on the pump. I asked the cashiers, they had no idea. Said look it up on the BP website. Could not find anything there.

Found some info on the pure-gas.org site. Really differs state to state. Fuel-tester.com site lists a number of states that require ethanol labeling at 1% or more. But my state, MISSOURI, is one of a number of states that requires NO ethanol listings period.

This is a stupid system that requires some to post a 1% ethanol warning, but lets other states post no warning at 15%.

I agree with you that a no label system sucks. They are making you buy something that you have no idea what is being dispensed. Blends with alcohol get less milage than blends that don't. Also blends with alcohol can cause a lot of maintenance problems with you equipment if you don't stay on top of it.

In most cases, if you purchase "Premium" gas, it is ethanol free, and it works fine in lawn equipment.

I did find the answer to my question, by chance. The newspaper had an article on the subject just in the last week. Seems the state legislature (Missouri) recently did not allow the amount of ethanol to go from 10% max to 15%.

But it is still ridiculous that the state does not require vendors to post the amount of ethanol on the pumps. The station attendants did not know, and I could not find anything on Google in ten minutes of searching BP.