When a hand saw won't do the job, a chain saw is the next likely choice. "Farm Boss" is the authoritative name for the Stihl 041 chain saw. Classified as an "occasional use" chain saw, the Farm Boss is designed for wood-cutting jobs in the backyard. Its specifications can help you decide whether to purchase this older model or point you in the direction of suitable replacements parts.

Engine

The Stihl 041 chain saw's single-cylinder, two-cycle (or two-stroke) engine has these primary measurements:

  1. Piston displacement: 3.72 cubic inches
  2. Cylinder bore: 1.73 inches
  3. Piston stroke: 1.57 inches

Fuel System

Because a chain saw must operate smoothly in different positions, Stihl installs an "all-position diaphragm carburetor" on its saws. The addition of an integral fuel pump works with the all-position carburetor by not requiring a "float," which is typically a carburetor mainstay. A float responds to the fuel level in many carburetors; when the fuel level is low, a valve opens to allow more fuel into the carburetor. The Farm Boss doesn't have a carburetor float; instead, it relies on the diaphragm -- a flexible disk -- to maintain the carburetor's fuel level. Working in tandem with the carburetor to keep particles out is a flocked wire mesh filter.

  • Fuel mixture: The Stihl 041 uses a mixture of gasoline and oil for its fuel. The mixing ratio is 1:40 if you use Stihl two-stroke engine oil -- this means to mix 1 part oil with 40 parts gasoline. You can also use other quality-grade two-stroke oils -- mix them at the rate of 1:25 (1 part oil to 25 parts gasoline).
  • Fuel tank capacity: 1.31 pints.

Ignition System

The Stihl 041 ignition system is a magneto-type with breaker points.

  • Ignition timing: 0.09 to 0.10 inch before top dead center.
  • Breaker point gap: 0.012 to 0.016 inch.

Spark Plugs

  • Type: Bosch WSR 6 F or Champion RCJ 6 Y interference-suppressed spark plugs.
  • Heat value: 175.
  • Electrode gap: 0.02 inch.
  • Spark plug thread: 0.37 inch long.

Bar and Chain

The "chain" of a chain saw contains the cutting mechanism, small teeth that are embedded in the chain at intervals. As the engine moves the chain around the guide bar, the teeth saw into the wood. The Stihl 041 is designed to use two types of guide bars with various lengths and the corresponding chains.

Guide Bar

  • Types. Duromatic guide bar with Stellite tipping at the bar nose or Rollomatic guide bar with star-shaped roller nose.
  • Lengths. For Duromatic guide bars, use 16-, 18-, 20- or 25-inch length. For Rollomatic guide bars, use 15-, 16-, 18-, 20- or 25-inch length.

Chain

  • Type. Stihl's Oilomatic chain is designed with grooves that channel the lubricating oil along the chain. Use 3/8-inch Rapid-Standard, Rapid-Micro or Rapid-Super; or S-type Rapid-Standard or Rapid-Micro chains.
  • Chain sprocket. Seven teeth for 3/8-inch pitch.
  • Chain lubrication. For homeowner use, Stihl recommends its regular bar and chain oil or its BioPlus bar and chain oil, which is a highly biodegradable vegetable-based lubricating oil.
  • Oil tank capacity. 0.53 pint.

Safety Features

  • Hand guard. Serving a twofold purpose, the hand guard protects the hands against branches and also helps to keep the left hand from touching a slipped chain.
  • Safety throttle lock. The safety throttle lock must be depressed before the chain saw can start.
  • Scabbard (chain guard). The scabbard prevents you from touching the chain.
  • Chain catching bolt. If a chain breaks, the chain catching bolt directs it inside the sprocket cover.