I can only assume that those that are against using Av-gas havent used it much and are repeating what they've read elsewhere. I've used Av-gas for years in everything from my 83' 750cc yamaha (7 yrs now) to my push mowers and weadtrimmer and saw motors. There may be a number of reasons why Av-gas runs better in all my engines than pump gas but in the end they do run better and I've seen no ill effects over the years, yes I have motors than have seen nothing but Av-gas their whole life and they run perfect year after year. No fouled plugs or sticky this or that. I must say not to run Av-gas in a modern auto engine however, the lead doesnt play nice with modern emmision stuff on the engines.

Av-gas seems to burn cleaner, produce slightly more power and run cooler than nasty pump gas and heres most likely why:
The FAA has set standards for Av-fuels that must be maintained by law. You can bet the fuel will be a fresher, cleaner high quality fuel. Pump gas on the other hand just needs to burn....no one like the FAA regulates the quality of pump gas to the same high standard. Sure, someone is looking to make sure the gas is gas but no laws require auto gas to be high quality.

Those who run pump gas, thats fine. But to those wondering about Av-gas, go right ahead, I wont run nothing else if I can help it. Piper