A couple years back Stihl power products (Chainsaws) decided that a simple threaded cap on both the fuel mix and bar oil reservoirs must not have been sophisticated enough for their products. The monkeys in charge at Stihl redesigned a simple proven technology (threaded cap) and replaced it with a mechanized, quarter-turn, latching cap. The caps themselves are not simple, and are made up of several moving parts.
I received one of the saws with the new caps as a gift three years ago and it has cursed me ever since. Often you latch the cap believing it is secure, only to find an oil or gas mess spilled out everywhere including down your leg when you go to start the saw! I have spent unnecessary time just simply trying to get the caps to seat and latch properly so they will stay in place. Add even more time cleaning up the messes. You have to ask yourself if a quarter turn cap saved you any time? It’s funny how something that should be so simple can make an otherwise good product so worthless, but that’s what monkeys do best!