Look at the CRAP the new fuel blends leave behind ...

[DaleH]

Fuel blends actually contain ‘solids’ in it and if untreated fuel or worse, OLD untreated fuel is allowed to evaporate in the carburetor bowl ... then this is what can occur, it looks like gold dust! In this case, the guy should be on that TV show “Gold Rush”!

I myself, I run my OBs dry at the end of the season, whilst fogging them, even though they have Stabil treated fuel. But if it’s a fuel injected motor, I keep it pressurized with NEW, but also heavily dosed/treated fuel.
....

 

[maintenanceguy]

I run my dry too. Evaporating fuel leaves sticky residue behind that clogs tiny ports in the carbs. I also drain the carb bowls using the drain screw. Just running the motor with the fuel line disconnected might not get all of the fuel out of all of the carbs.

 

[turbotodd]

you want an eye opener?

Grab an old measuring cup, or a glass jar, or something along those lines. Fill it about 3/4 full of fresh gasoline. Don't put a lid on it. Let it sit a few hours after you mark the level that you filled it to.

I do this at work to prove to techs (especially inexperienced and/or new techs) that gasoline evaporation is a big deal. In 24 hours, it's not unusual for 40 to 50% of the original volume to be gone; especially this time of year when it's warm/humid outside. A lot of times the evaporation will cause the fuel in the cup to cool and then it also causes moisture to condense out of the air. The cooling effect is pretty dramatic. After a few hours sitting out you can feel the container and it is obviously cooler than ambient.