Anybody have a Poulan gas cap swell up?

[GlenM]

Bot a refurbished PPro4218 several years ago. Used it quite a bit, good saw.  Went to put gas in it after about a year and, had to use vise grips to get cap off.  Had to buy a new one.
What would cause plastic to swell?
thanks
???

[Rocky_J]

Ethanol in the gasoline, supposedly mandated to save the environment. Nothing we can do about it other than try to keep our fuel fresh (this involves lots of illegal dumping of old fuel). Manufacturers are finally beginning to make fuel components resistant to the corrosive effects of ethanol, so most replacement parts these days won't react the same way.

Lucky you, the Stihl gas caps are about $35 each and the ethanol ruins them in short order as well. :(

[GlenM]

Very interesting.  I had seen these caps at the store on previous trips, and wondered, at the time, why they would have this odd item of a Poulan gas cap on the rack.  Has to be a common problem for this store to just have the caps.
As I remember, it was approx $5.
Maybe should dump fuel between uses.
thanks for reply,

[peppone]

old gasoline become acid 'cause ethanol that's in.

[Cut4fun]

Yep, isnt it fun getting them back on  :D

[icolquhoun]

i have a 4218avx and have this problem even though i "just snug" up the gas cap.  While I havent had to resort to any mechanical help yet, they are rather hard to get off every now and then out in the woods.
BTW, for what it's worth, I have the same issue for the bar and chain oil cap as well, even more so :(