According to the company's website, Stihl is the number one selling line of handheld outdoor power equipment in America. The company manufacturers trimmers, edgers, construction tools and of course, chain saws. The MS 290 is but one of the many chain saw models Stihl produces. The instruction manual for the MS 290 lists all of the pertinent specifications for the unit, including the engine displacement, horsepower, ignition system type, fluid capacities and fuel requirements.
The MS 290 is equipped with a 2-stroke, single-cylinder, 3.45 cubic inch engine that is capable of producing 3.8 horsepower at 9,500 rpm. The cylinder bore is 1.81 inches and the piston stroke is 1.34 inches. Engine idle speed is rated at 2,800 rpms, and the maximum operational speed is 13,500 rpms. The engine is equipped with an all-position diaphragm carburetor with integrated fuel pump. Air filtration is accomplished using both a coarse prefilter and a two-piece box filter.
The MS 290 is equipped with an 18.9 oz. (0.56 L) fuel tank. The chain oil tank has a capacity of 11.2 oz. (0.33 L). Stihl recommends that any chain oil used in the unit must be resistant to thermal breakdown and biological contamination by micro-organisms. Stihl has developed a special blend of chain oil known as Stihl "Bioplus," which meets the chain and guide bar lubrication requirements of the MS 290. The instruction manual cautions that using inferior grades of chain oil may eventually cause the automatic oil pump to seize.
The engine of the MS 290 is designed to operate on unleaded gasoline, with a 2-stroke oil to gasoline mix ratio of 50:1. Gasoline should have a minimum octane rating of 89 or higher. The company also recommends using Stihl brand 2-stroke engine oil which has been specially formulated for use in Stihl manufactured engines. As a final warning, the company recommends mixing only small amounts of fuel at any one time and cautions against using any 2-stroke fuel which is more than three months old.
Ignition System, Weight and Bar Length
The ignition system of the MS 290 is an electronic magneto type. The factory installed spark plug is a Bosch WSR 6 F, with a 0.02 inch (0.5 mm) spark gap. The dry weight of the unit -- meaning before the addition of fuel or chain oil -- is 13.0 lbs. The MS 290 will accommodate a chain bar of 16, 18, or 20 inches in length.