Stihl MS 250 Chainsaw

Safety

The Stihl MS 250 has enough output for frequent firewood and storm cleanup, so control the work area before starting the engine. Its 45.4 cc powerhead produces 2.3 kW / 3.1 HP, and kickback can happen quickly if the upper bar nose contacts wood, brush, or hidden material. Use a sharp chain, correct bar length, and steady two-hand grip. Do not cut from ladders, roofs, or unstable log piles.

• Wear chaps, helmet or face shield, hearing protection, gloves, and boots with grip.
• Verify the chain brake, throttle lockout, chain catcher, and stop control.
• Keep the bar clear of soil, wire, nails, and split wedges.
• Refuel only after cooling; wipe spills before restarting.
• Use fresh fuel mixed at 50:1 and store it in a marked container.

Unboxing & first run

Check that the box includes the powerhead, bar, chain, scabbard, tool, and documentation. The MS 250 powerhead weighs about 10.1 lb and carries a 16.9 fl oz fuel tank, so it feels nose-heavy if a long bar is fitted without the chain properly tensioned. Assemble the saw on a clean bench, not on dirt, and verify that the chain matches the bar stamp before adding fluids.

• Install a 16″ or 18″ bar with the correct 3/8″ standard pitch, .063 gauge chain.
• Fill chain oil first, then fuel mixed at 50:1.
• Start cold with the chain brake engaged and the bar clear of the ground.
• Warm the engine briefly; confirm clean acceleration and stable idle.
• After the first tank, recheck bar nuts, chain tension, oil delivery, and leaks.

Controls layout

The MS 250 uses a familiar rear-handle chainsaw layout. The front hand guard doubles as the inertia and manual chain brake. The top cover gives access to the air filter and spark plug. The rear control cluster includes throttle trigger, throttle lockout, and the master control lever for stop, run, warm start, and choke positions. The side cover secures the bar and exposes the clutch sprocket area when removed.

• Front handle: main left-hand grip and brake path.
• Rear handle: throttle trigger and lockout, shaped for gloved use.
• Master control lever: stop, run, start, and choke control.
• Fuel and oil caps: separate tanks; never cross-fill.
• Cutting setup: typically 16″ or 18″; the listed 18″ chain is 60DL.
• Bar mount area: bar studs, tensioner pin, chain catcher, and clutch cover.

Routine maintenance

Routine maintenance should follow the amount of cutting, not the calendar alone. Firewood work in bark and dust can clog the air filter and bar oil passages in a single day. Start each session with a dry exterior, secure handles, and a chain that pulls around the bar by hand with resistance but no binding. Keep the starter cover and cooling fins clear so the engine sheds heat.

• Every tank: check chain tension, bar oil level, chain brake action, and throttle return.
• Daily: clean air filter, bar groove, oil holes, clutch cover, and sprocket area.
• Weekly: inspect fuel line, tank caps, starter rope, chain catcher, and anti-vibration parts.
• Spark plug: inspect color and gap; reinstall to 20 N·m if the plug specification allows.
• Replace damaged safety parts immediately rather than finishing the job with a compromised saw.

Blade or chain replacement

Replace the chain when it will not hold an edge, has blue heat marks, broken cutters, stiff links, or rivet wear. For the listed setup, the MS 250 uses 3/8″ standard pitch, .063 gauge; an 18″ loop is commonly 60DL. Do not substitute low-profile chain or a mismatched gauge. The wrong chain can ride high, oil poorly, damage the sprocket, or leave the bar.

• Stop the engine, apply the chain brake, and let the muffler cool.
• Remove the clutch cover, then loosen the tensioner until the old chain lifts off.
• Inspect sprocket teeth, bar rails, nose sprocket, and oil ports.
• Fit the new loop with cutters facing forward on the top of the bar.
• Lift the bar nose while tensioning and tightening bar nuts.
• Run briefly, stop, cool, and reset tension before cutting hard wood.

Sharpening or cleaning

Sharpen before forcing the saw. A dull MS 250 chain increases vibration, heat, fuel use, and kickback risk because the operator pushes instead of guiding. Keep filing angles consistent across the full loop and correct depth gauges only with the matching guide. Clean the bar and chain after cutting resinous wood, burned material, or dirty storm debris. Dirt in the bar groove can block oil and wear the rails unevenly.

• Secure the bar; engage the brake only if it helps hold position.
• File each cutter the same number of strokes unless damage requires more.
• Maintain equal cutter length on left and right sides.
• Check depth gauges after repeated sharpenings, not after every light touch-up.
• Brush the clutch cover and chain brake band area without soaking brake components.
• Flip the bar on a regular schedule to distribute rail wear.

Troubleshooting

Troubleshooting should begin with the simple checks: fresh fuel, clean air, sharp chain, and correct tension. The MS 250 will often feel weak if the chain is dull or over-tightened, even when the engine is healthy. Avoid compensating with carburetor adjustments until the cutting system and filters are known good. If the saw has been stored with fuel, drain and replace it before judging starting behavior.

• Hard start cold: verify choke position, primer routine if equipped, spark plug condition, and fuel freshness.
• Starts then dies: clean the air filter, check tank venting, and inspect fuel pickup.
• No bar oil: clean oil holes, fill the tank, and inspect for packed chips behind the cover.
• Chain throws: confirm 60DL loop length on 18″ setup, tension, bar wear, and sprocket wear.
• Slow cut: sharpen, lower depth gauges correctly, or replace a damaged bar.

Compatible parts

Compatible parts must match the bar mount, chain pitch, gauge, and drive-link count. The listed MS 250 configuration uses 3/8″ standard pitch, .063 gauge; the 18″ chain spec is 60DL. If the saw is fitted with a different bar, read the bar stamp before ordering. Keep one sharpened loop ready, because swapping chain in the field is faster and safer than filing a badly rocked chain beside the cut.

• AP—18CB—STD: 18″ standard-pitch guide bar for the matching mount.
• AP—72LPX—60: 18″ chain loop, 3/8″, .063 gauge, 60DL.
• AP—AF—MS250: replacement air filter for the MS 250.
• AP—SP—STIHL34: spark plug for compatible Stihl saw applications.

Replace bar and chain as a set if both show heavy wear or the chain no longer seats squarely.