Introduced in 1971, the model 031 AV chain saw was made by Stihl Andreas Maschinenfabrik of Stuttgart, Germany. Designed for operation by one person at a time, this saw featured an orange and gray color scheme and weighed 14.5 pounds, without its bar and chain. As a way to enhance operator safety, the saw included both vibration reducing handlebars and the option for a chain brake.
Cutting Chain and Guide Bar
Stihl recommends the use of their own chains. They designed the 031 AV to specifically use chains with a 0.375-inch pitch. The saw can accept guide bars of 14 to 20 inches in length.
The 031 AV comes with an 18.25 fluid ounce fuel tank. The tank holds a mixture of regular gasoline and Stihl's mixing oil for two-cycle chainsaw engines. It requires a ratio of 40 parts of gasoline to one part of oil.
Although the original 031 AV chainsaws had flywheel magnetos, they were updated over the saw's life to a version which used transistors. In either case, the ignition system was set to generate a spark when the piston was between 0.008 and 0.009 inches from having the cylinder reach its "top dead center" position. The spark itself was created by a 0.02 inch gapped Bosch WSR6F or Champion RCJ7Y spark plug.
A 2.93 cubic inch displacement one cylinder two stroke engine drives the 031 AV chainsaw. It uses a Tillotson carburetor and automatic rewind starter and features a nylon mesh air filter system. The engine's bore and stroke measurements are 1.73 and 1.26 inches, respectively.