Why does the chainsaw get stuck?

Why does the chainsaw get stuck? 

The causes of chain jamming + troubleshooting, divided into three categories: running jam, starting jam, and chain jam. Listed in order of likelihood of occurrence.

1. Chain / Guide plate jamming (most common, suddenly unable to move during operation)

1.1 Chain jammed by wood chips, wood (directly jammed on site)

During sawing, the wood material presses and blocks the guide plate slot, or the tree trunk clamps the chain, causing the chain to instantly lock and not move even when the throttle is fully applied.

Causes: Wood material cracks trapping the saw, excessive cutting depth, oblique sawing, wet wood / soft wood with a large amount of chip accumulation.

Treatment: Turn off the engine, use a crowbar to open the wood material gap, clean the wood chips in the guide plate slot, manually pull the chain to confirm smoothness before using.

1.2 Insufficient chain lubrication, dry grinding jam

Oil pump failure, oil passage blockage, oil holes in the guide plate blocked, no lubricating oil between the chain and the guide plate, rapid temperature rise causes metal expansion to jam.

Signs: Guide plate overheats, emits smoke, chain becomes hard and does not turn.

Treatment: Clean the oil passage and oil holes, inspect and repair the oil pump; severe jamming requires disassembly and grinding, overheated parts may be directly replaced.

2. Chain too tight / installation misalignment

The chain is too tight, after running, it expands due to heat, and the gap disappears, causing jamming; the guide plate is installed crooked, or the retaining spring is misaligned, which also causes jamming.

Standard: The chain can be easily lifted when hanging down, and the guide plate teeth tip should be exposed, do not be too tight.

Treatment: Loosen the adjustment screw, re-calibrate the chain tension and the position of the guide plate.

3. Guide plate wear, deformation, rolled edge

The guide plate guide rail is worn and forms grooves, the head is curled, and the chain runs into jamming, gradually developing into jamming.

Treatment: Polish and repair or replace the guide plate directly.

2. Engine internal jamming (unable to pull the starting rope, crankshaft jammed, severe failure)

1.1 Insufficient oil / incorrect oil ratio, cylinder jamming and shaft seizure (core high-frequency failure)

Two-stroke oil saws must mix fuel and oil in the correct proportion:

Too little oil, only using pure gasoline, or incorrect proportion (too little oil), the piston, cylinder, crankshaft and connecting rod have no lubrication, high-speed friction and high temperature cause the piston to stick to the cylinder, the crankshaft to seize, the starting rope is completely unable to pull.

Low-quality oil, or oil that has been stored for a long time and failed to function can also cause this.

Treatment: Completely disassemble the engine, replace the damaged parts such as the piston, piston rings, cylinder, and crankshaft, and re-mix the fuel according to the standard proportion.

2. Poor heat dissipation, overheat and die from jamming

The heat sink fins are blocked, the air filter is clogged, long-term full-load operation, the engine temperature is too high, metal thermal expansion causes the piston and cylinder to seize.

Treatment: Clean the heat sink fins and air filter; slight jamming can be attempted to rotate the starter by soaking with rust / lubricating oil, severe cases require major repair.

3. Foreign objects fall into the cylinder, intake passage

Wood chips, metal debris enter the cylinder through the intake port or spark plug hole, the piston is stuck during upward movement.

Treatment: Remove the spark plug, check for foreign objects in the cylinder and remove them, then try to pull the starter.

4. Crankshaft bearing damage, connecting rod deformation

The bearing is lacking oil, worn and cracked, the connecting rod is bent, the crankshaft rotation is obstructed, the entire machine jams, often accompanied by previous abnormal sounds.

Treatment: Disassemble the box, replace the bearings and connecting rod assembly.

3. Clutch / transmission part jamming

1. Clutch shoe block jamming, spring failure

The clutch block is stuck due to oil contamination or wood chips and cannot return, or the spring breaks, the clutch is always in the engaged state; after stopping, the load jams the crankshaft.

Signs: Idle speed also rotates with the chain, the chain jams after熄火， starting is difficult.

Treatment： Disassemble the clutch， clean the oil and debris， replace the damaged spring and shoe blocks.

2. Chain wheel jamming， bearing damage

The drive chain wheel bearing is lacking oil， worn， and rusted and stuck， the power end of the chain directly locks.

Treatment： Disassemble the chain wheel component， add lubricating grease， replace the damaged bearing if necessary.

4. Other jamming causes

Long-term storage rusted

The machine is idle for several months， the cylinder， chain， metal parts are damp and rusted， the rotating parts are rusted and jammed.

Treatment： Add lubricating oil to all movable parts， soak and slowly manually rotate， do not pull or drag forcefully.

Misoperation after engine shutdown

Without stopping the machine, forcibly pressing the chain or touching the rotating parts, external force causing the chain to get stuck.

Quick identification & emergency handling

Only the chain is not turning, but the starting rope can pull it: The problem lies in the chain, guide plate, and sprocket. Clear the wood chips, adjust the tightness, and check the lubrication.

The starting rope cannot be fully pulled: There is a high probability that the engine has pulled the cylinder, the crankshaft is stuck, or foreign objects have entered the cylinder. Do not forcibly pull it forcefully to avoid secondary damage.

The idle chain keeps turning and then gets stuck: Inspect the clutch.

Precautions

Strictly mix the two-stroke engine oil in the prescribed ratio, and strictly prohibit the use of pure gasoline;

Check the chain supply of oil before each operation, regularly clean the oil holes of the guide plate and the heat sink;

Reasonably adjust the tightness of the chain, avoid clamping the wood when cutting, and make multiple cuts for thick wood;

Before long-term storage, empty the fuel, apply oil to the moving parts, and place it in a dry place.