Question 1

the chain brake won't engage when i push the handle forward, it just feels loose.

Accepted Answer

DIAGNOSIS The brake band is not being pulled tight around the clutch drum. The linkage between the front handle and the brake mechanism is disconnected or broken. FIX Remove the side cover. Visually inspect the metal brake band and the spring that connects it to the handle linkage. The spring should be attached at both ends. If the spring is detached or broken, replace it. Check that the linkage rod from the handle moves when you engage the brake. IF THAT DIDN'T WORK The inertia-activated feature may be stuck. The mechanism inside the flywheel cover must move freely. Gently tap the front of the saw with your hand to see if the brake engages automatically. If it does, linkage is the issue. If not, the internal inertia springs may be faulty. HEADS UP Do not use the saw until the chain brake is functional. It is a critical safety device. Test the brake by running the saw at idle and pushing the front handle forward. The chain should stop immediately.

Question 2

saw vibrates like crazy, way more than it used to. makes my hands numb fast.

Accepted Answer

DIAGNOSIS Excessive vibration indicates an imbalance in the rotating assembly or loose components. The primary suspect is a damaged or heavily unbalanced chain. FIX First, stop the saw. Remove the chain and inspect it for a damaged or missing cutter, a stiff or frozen link, or severe uneven wear. Spin the chain by hand on a flat surface to check for bends. Replace the chain if any defects are found. IF THAT DIDN'T WORK With the chain and bar removed, start the saw briefly. If vibration is still high, the issue is internal. Likely causes are a bent crankshaft, failed engine mounts, or a loose flywheel. This requires professional service. HEADS UP Never operate a chainsaw with a badly vibrating chain. It dramatically increases the risk of kickback and causes premature failure of the crankshaft bearings.

Question 3

it's throwing oil everywhere but not onto the bar and chain. just spraying out the bottom near the clutch.

Accepted Answer

DIAGNOSIS Bar oil is being pumped but is not being directed to the bar. The oil outlet hole on the clutch cover or the corresponding channel on the saw body is blocked. FIX Remove the side cover and bar. Clean the oil outlet hole on the engine side—it's a small port near where the bar mounts. Use a thin wire or compressed air. Then, clean the matching oil channel on the inside of the clutch cover. Ensure the hole in the bar itself is clear. IF THAT DIDN'T WORK The oil pump output may be too high. The pump on the 120 Mark II is not adjustable. If the pump is defective and over-pumping, it will need replacement. HEADS UP Running the saw without adequate bar oil will destroy the bar and chain in under a minute. After cleaning, test oil flow by running the saw at high idle with the bar tip aimed at a piece of cardboard. You should see a line of oil slung onto the cardboard within 30 seconds.

Question 4

chain gets really loose after just a few cuts, i have to tighten it constantly. tension screw is tight.

Accepted Answer

DIAGNOSIS The chain is stretching excessively due to incorrect adjustment, a worn bar, or insufficient lubrication. FIX Follow the correct tensioning procedure. Loosen the bar nuts. Use the tensioning screw to raise the bar nose until the chain is snug against the bar bottom. Hold the nose up and tighten the bar nuts to 8-10 Nm. The chain should still pull freely by hand. Check bar oil flow. A dry chain heats and stretches. IF THAT DIDN'T WORK Inspect the bar rails. If they are unevenly worn or have a "burnt" opening at the nose, the chain will not seat properly and will feel loose. Dress the rails with a flat file or replace the bar. HEADS UP A new chain will have a normal break-in stretch period. You will need to re-tension it after the first 5-10 minutes of use. This is expected.

Question 5

my 120 mark ii is leaking bar oil all over my garage floor even when it's just sitting.

Accepted Answer

DIAGNOSIS Bar oil is siphoning from the tank through the oil pump. The most common point of failure is the oil tank vent. FIX Locate the oil tank vent. It is a small, often green, one-way valve near the oil cap or filler neck. Remove it. Blow through the valve to check it only allows air in one direction. If air passes both ways or it is cracked, replace the vent valve. IF THAT DIDN'T WORK The oil hose connecting the tank to the pump may have a crack or a poor seal at the fittings. Remove the side cover and inspect the clear hose for leaks, especially where it connects to the pump nipple. HEADS UP Do not store the saw on its side or with the bar nose lower than the tank. This accelerates siphoning. Always store it upright or on the correct side as indicated in .

Question 6

saw runs okay but the chain won't move, it's just stuck. the bar isn't pinched.

Accepted Answer

DIAGNOSIS The clutch or the drive sprocket is not engaging. The primary cause is a failed clutch spring or a severely worn sprocket. FIX Remove the side cover and bar. Inspect the clutch drum and sprocket. The sprocket should turn freely by hand when the engine is off. If it is seized, replace the sprocket. Next, check the clutch shoes. With the engine off, they should move outward slightly when you try to turn the drum. If they are stuck or the spring is broken, the clutch assembly must be replaced. IF THAT DIDN'T WORK The chain brake may be partially engaged due to a faulty mechanism. With the cover off, manually move the brake band back to its fully disengaged position and see if the drum turns freely. HEADS UP Always wear gloves when handling the chain and sprocket. A worn sprocket will rapidly destroy a new chain. Match the replacement sprocket type (rim or spur) to what was originally installed.

Question 7

chainsaw starts but dies as soon as i give it throttle or take it off choke. runs for like 5 seconds.

Accepted Answer

DIAGNOSIS The engine is not getting enough fuel under load. The carburetor's idle circuit or main jet is likely clogged from old fuel or the low-speed screw needs adjustment. FIX First, drain all old fuel and refill with fresh 50:1 mix. If problem persists, locate the carburetor adjustment screws. The L screw controls low-speed fuel. With the saw idling, turn the L screw clockwise in 1/8-turn increments until the engine runs smoothly off choke and accepts throttle without dying. IF THAT DIDN'T WORK The fuel filter in the tank may be clogged. Remove the fuel cap and use a bent wire to hook and lift out the filter. Inspect for debris. Replace if it is dark brown or blocked. HEADS UP The factory setting for the L screw is typically 1 turn out from fully seated. Use this as a baseline if you turned it too far. Do not adjust the H screw marked for high speed; it is factory-set for emissions.

Question 8

my new husqvarna 120 mark ii won't start at all, not even a sputter. it's full of gas and oil.

Accepted Answer

DIAGNOSIS The engine is not receiving the correct air/fuel mixture or spark. This is a new-unit setup problem. The most common cause is the master control lever being in the wrong position. FIX Check the master control lever position. It must be fully down in the start position. The symbol is a circle. Next, ensure the chain brake is disengaged. Pull the brake handle toward you until it clicks. Confirm the fuel tank vent is open. Turn the black fuel cap until the arrow points to the open symbol. IF THAT DIDN'T WORK The spark plug wire may not be fully seated. Check the connection at the top of the spark plug. Push it on firmly until you feel it click over the plug's terminal. HEADS UP Do not pull the starter cord more than 3-4 times with the choke on if it hasn't sputtered. You will flood the engine. Move the master control lever to the half-throttle position and pull several times to clear it.

Husqvarna 120 Mark II Gas Chainsaw

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