Introduction
When an Echo CS-590 Timber Wolf chain tensioner fails, it transforms a reliable 59.8cc powerhead into a frustrating paperweight. This guide walks through the complete replacement procedure, from diagnosing a worn tensioner to torquing the final bolt. Whether dealing with a stripped adjustment screw or a seized pawl, the steps below return the saw to proper chain adjustment capability.
Why Does the Echo CS-590 Timber Wolf Chain Tensioner Fail?
Three primary failure modes plague this saw: stripped plastic adjustment knobs, corroded steel pawls, and deformed tensioner rails. The OEM tensioner assembly (part number 91702-12321) uses a nylon pawl that contacts the steel adjustment screw. Over time, debris packing in the guide bar slot forces the pawl to skip, wearing the nylon threads. Extended operation with loose chains also causes the tensioner plate to bend, preventing smooth adjustment. Saw owners can also check if the compression test reveals excessive engine wear before investing in tensioner parts.
What Tools Are Required for Echo CS-590 Timber Wolf Chain Tensioner Replacement?
- T20 Torx driver for side cover screws
- 8mm socket or nut driver for bar nuts
- Flathead screwdriver for prying clutch cover
- Needle-nose pliers for spring clip removal
- Brake cleaner and rag for cleaning bar pad
- Anti-seize compound for adjustment screw threads
Optional: a 3/8-inch breaker bar for stubborn bar nuts. Replacement tensioner assembly costs approximately £12.99 in UK markets or $16.99 USD.
How to Remove the Old Chain Tensioner on an Echo CS-590 Timber Wolf
Begin by removing the bar nuts and clutch cover. Slide the guide bar off the studs. The tensioner assembly sits on the oil pump mounting plate, held by a single T20 screw.
- Remove the clutch cover and bar nuts.
- Pull the guide bar rearward to release chain tension.
- Locate the T20 screw securing the tensioner plate to the oil pump housing.
- Unscrew the T20 screw completely.
- Lift the tensioner assembly straight up; the adjustment pawl and screw may separate.
- Inspect the pawl teeth; replace if worn flush.
For saws with heavy debris buildup, clean the bar pad area before proceeding. If the engine shows other symptoms, check the decompression valve for proper sealing before reassembly.
What Are the Correct Steps to Install a New Chain Tensioner on an Echo CS-590 Timber Wolf?
| Component | Torque (ft-lb) | Torque (Nm) | Notes |
|---|---|---|---|
| Bar nuts | 25-30 | 34-41 | Apply anti-seize |
| Tensioner plate screw | 8-10 | 11-14 | Do not overtorque plastic housing |
| Adjustment screw (to pawl) | Hand tight + 1/4 turn | — | Nylon threads strip easily |
| Clutch cover screws | 12-15 | 16-20 | Even torque both sides |
- Place new tensioner assembly onto oil pump plate, aligning the pawl slot with the adjustment screw.
- Insert the T20 screw and torque to 8 ft-lb.
- Slide guide bar into position, engaging the tensioner pin with the bar’s adjustment hole.
- Thread adjustment screw clockwise until pawl contacts bar, then back 1/4 turn.
- Install clutch cover and bar nuts; torque to 25 ft-lb.
- Tighten adjustment screw until chain fits snugly against bar rail, then loosen 1/4 turn.
- Spin chain by hand; ensure no binding.
If the tensioner still feels gritty after installation, flush the bar groove with brake cleaner. The carburetor rebuild guide covers air filter maintenance that prevents debris from reaching the tensioner area.
What Do Echo CS-590 Timber Wolf Owners Say About Chain Tensioner Problems?
Owner forums report the tensioner adjustment screw stripping after 3-5 years of moderate use. Many describe “clicking” sounds during adjustment as the pawl slips over worn threads. The plastic tensioner plate cracks under excessive force when bars are overtightened. Several users recommend upgrading to the steel-reinforced aftermarket tensioner kit (PN 5705-671-1200) for £18.99, which eliminates nylon pawl failure. One long-term user noted the tensioner lasted through three chains before needing replacement. For saws used in dirty environments, inspecting the tensioner every 10 hours of operation prevents sudden failure. The recoil starter replacement guide addresses other common starter-side failures that occur alongside tensioner issues.
How to Maintain the Echo CS-590 Timber Wolf Chain Tensioner After Replacement
Apply a drop of lightweight machine oil to the adjustment screw threads every fifth tank of fuel. Wipe the bar pad area clean during each chain sharpening session. Avoid overtightening chain tension; the CS-590 runs best with slight droop on the bottom of the guide bar. If the adjustment screw turns freely without moving the bar, the pawl has likely stripped—inspect immediately. For maximum longevity, use only OEM tensioner parts from authorized dealers. Checking cylinder health before major tensioner work ensures the saw is worth the repair investment.
Frequently Asked Questions About Echo CS-590 Timber Wolf Chain Tensioner
1. How much does an Echo CS-590 Timber Wolf chain tensioner cost?
OEM replacement costs £12.99 (UK) or $16.99. Steel-reinforced aftermarket versions run £18.99 to £24.99.
2. Can I reuse the old tensioner if it only clicks?
No. Once the nylon pawl strips teeth, it cannot grip the adjustment screw. Reuse leads to bar looseness in operation.
3. Are there upgraded tensioners for the Echo CS-590?
Yes. Aftermarket steel pawl kits from Oregon and Forester fit directly and last 3-4x longer than OEM nylon parts.
4. How do I know the tensioner needs replacing?
Symptoms include chain adjustment not holding, clicking during screw turning, or inability to tighten past finger-tight without stripping.
5. Can I replace the tensioner without removing the clutch?
Yes. The tensioner assembly mounts externally on the oil pump plate. Only remove the clutch cover and guide bar.
6. Does the Echo CS-590 Timber Wolf use the same tensioner as the CS-620P?
No. The CS-620P uses a different pawl and screw pitch. Stick to CS-590-specific parts for proper fit.
