The Quick Chain Adjuster is a feature found on select STIHL chainsaw models that allows the user to adjust the chain tension without using tools. The adjuster is easy to use and allows the chain tension to be adjusted in seconds. It’s signified by “QCA” or “B” in the chainsaw model name. For example the MS 251 C-BE and MSA 140 C-BQ both have the Quick Chain Adjuster.
To adjust the tension with the Quick Chain Adjuster: