I need to check my serial numbers. May have a couple, but I haven't had any problems and I use midgrade fuel which is supposed to have less ethanol. And I always add seafoam or Stabil.
I rented a Stihl Pole Saw a couple of weeks ago and I had a fuel leakage problem the first time I refilled it, but none after that. I just assumed that I did not replace the cap properly the first time.
Interesting-
I've had the gas cap on my backpack blower open up on me twice.
Both in the same location where I'm squeezing between the shrubs and the house.
I figured it spun loose when I moved through and it rubbed against the bricks.
What got my attention was the smell of spilt fuel and the cool sensation of it evaporating out of my shirt.
Now i'm just a little more careful when I work in there.