Yes the conventional wisdom is that fuel fillers are really bad. I have had at least 2 dozen orver the last 20 years and may have had to "rebuild" 3 of them, a 5 minute job. Will add "fuel fillers bad" to my lsit of favorite RC myths, along with EZ keepers don't work and must only use fuel with castor oil. List is up to 11 now and just cracks me up how much bad info is passed along in this hobby based on these myths. I have 18 flyable gas and glow planes and 6 electric. In 20 years have owned about 60 planes, only crashed 2 beyond repair. I go to the field and my planes start and fly almost always, why, maitenance! Nothing will work well for long, especially aircraft, if not maintained. Drain the tanks, clean them up, check the bolts and horns etc., cycle the batteries, use your volt meter, iron out the wrinkles, patch the tears. The guys that come out and can't get an engine to run almost every time also are the guys who never fix anything! You are not lucky bigtim just paying attention.