How to Replace the Chain Tensioner on an Echo Chainsaw

The chain tensioner connects to the adjustment screw and fits into a hole on the bar. When the adjuster is rotated, it moves the tensioner to either tighten or loosen the chain on the bar. Most damage to the tensioner occurs when the bar is overtightened. When this happens, the threads will often strip out of the pin, or strip on the adjustment screw.

Let's get started.

REMOVING THE CHAIN TENSIONER   1. Remove the chain brake.

a. Use a wrench to loosen the two bar nuts.

b. Use a screwdriver to rotate the chain adjustment screw counterclockwise to reduce tension from the chain.

c. Remove the two bar nuts.

d. Remove the chain brake assembly from the saw.

  2. Remove the bar and chain.

a. Carefully remove the chain from the front of the bar.

b. Remove the chain from the rear sprocket.

c. Remove the bar from the saw.

  3. Remove the adjuster assembly.

a. Lay the chain brake assembly on your workbench so that the metal brake band faces up.

b. Remove the two screws securing the metal cover plate to the tensioner assembly.

c. Remove the metal cover plate.

d. Remove the adjuster assembly from the brake housing.

  4. Remove the chain tensioner.

a. Separate the bevel gear/collar from the adjustment bolt and chain tensioner.

b. Unthread and remove the chain tensioner from the adjustment bolt.

INSTALLING THE NEW CHAIN TENSIONER

  5. Install the chain tensioner.

a. Thread the new chain tensioner onto the adjustment bolt (approximately half-way onto the bolt).

b. Thread the adjustment bolt (and the new chain tensioner) through the plastic collar and into the bevel gear.

REASSEMBLING THE UNIT

  6. Reinstall the adjuster.

a. Install the adjuster assembly into the chain brake housing. The plastic collar should fit snugly into the channel on the housing and the tensioner pin should face away from the workbench.

b. Install the metal cover plate onto the chain brake housing.

c. Secure the metal cover plate with the two screws.

  7. Reinstall the bar and chain.

a. Install the bar onto the bar studs.

b. Slide the bar toward the rear of the saw.

c. Carefully install the rear portion of the chain around the sprocket and drum.

d. Install the front portion of the chain onto the bar, ensuring that the chain aligns with the groove along the top of the bar, as well as the sprocket at the tip of the bar.

e. Slide the bar toward the front of the saw until the chain seats snugly onto the bar.

  8. Reinstall the chain brake assembly.

a. Install the chain brake assembly onto the saw (the bar studs should align with the openings on the housing).

b. Use a screwdriver to rotate the tensioner screw (as-needed) until the chain brake assembly seats (snaps) securely in place.

c. Install (but do not fully tighten) the bar nuts onto the bar studs.

  9. Tension the chain.

a. Grasp and raise the distant end of the bar and chain assembly (opposite the engine).

b. While holding the bar in a raised position, use a screwdriver to rotate the tensioner screw until the chain begins to tighten against the bar.

c. Lift the chain away from the bar assembly and inspect the gap between the two components.

d. The chain is tensioned correctly when you are able to raise the chain slightly away from the bar without creating a visible gap between the guide links and the top of the bar.

e. Once the chain is properly adjusted, tighten the bar nuts to secure the assembly.