I was having paraffin problems, from pump gas. I even had to replace the carb on my Kombi, as it has some internals that I couldn't get cleaned out. I switched to AV100LL fuel and haven't had a single problem, since. I use Klotz 50:1 oil and mix it at that.
What I've been told, low-grade (87 octane) is refinery byproduct that has additives put in it to allow it to be burnable. Aviation fuel is pure, as we can't have planes falling out of the sky from crap fuel. Pump gas on your skin takes a couple days to get out. Aviation fuel on your skin lasts seconds and there is absolutely no residual smell. Around here, regular is ~$3.80 per gal, premium is $4+ per gal, AV100LL is $5.50 per gal. It burns cleaner and my stuff noticeably runs better. It's worth the extra expense, to me.
BTW, I've cleaned the carb on my little Echo, numerous times. But, it's 11 years old and still going.
1st Class Lawn Service
'14 Hustler X-ONE, 60", Kohler ECV749 EFI
'05 Hustler FasTrak, 42", Honda GXV530
'13 Toro Timemaster 30"
'02 Lawn Boy SilverPro 21"
Stihl BR600 blower
Stihl BG55 blower
Stihl KM55R string trimmer
Stihl KM55R Kombi system
Stihl MS180C chain saw
Echo GT-2000 trimmer
'14 Ariens Compact 24" Sno-Thro snowblower
'08 Troy Bilt Squall 2100 21" snowblower
'06 Chevrolet Silverado
'13 Bravo Star, 7'X12', V-nose