Stihl 066 Production Years & Specs (Model Guide)

The STIHL 066 is a professional-class chainsaw commonly documented as being produced from 1986 to 2003, before the MS 660 succeeded it. It has 91.6 cc displacement and commonly published output of 5.2 kW (7.1 bhp). Exact year and setup depend on market and configuration, so verify the serial, parts, bar, chain, and manual before buying or cutting.

Trying to confirm an 066’s year and decide whether its setup is right for your work? Start with the saw itself, not a badge or an online serial-number chart. I compare the model marking, serial, and installed parts, then check the bar and chain as a matched set. That method helps separate a genuine 066 from a modified or misrepresented saw.

Production years and model history

The STIHL 066 is commonly documented as a 1986–2003 model. Those dates describe the broad production period, not a promise that every market received the saw in the same year. The MS 660 followed it, but a replacement model’s arrival and the old model’s availability could vary by region.

STIHL’s model names changed over time, and 066 saws may have different parts or details across production runs. A replacement top cover, decal, or other service part does not prove the saw’s year. Nor does the MS 660 name alone establish that a saw’s internal parts are unchanged.

Treat 1986–2003 as the practical range when researching an 066, not as a way to date a specific unit. If a seller claims an exact year, ask what record supports it. A serial number and the saw’s actual configuration are more useful than appearance alone.

STIHL 066 specifications

Specifications describe the saw’s engine and cutting system, but they do not guarantee how a particular used example will perform. Wear, repairs, market version, and installed parts all matter. Use the figures below as a reference, then confirm settings and service details in the manual for the saw’s version.

Output figures can look inconsistent because published ratings may use different conventions. A listing of 5.2 kW and one of 7.1 bhp are commonly associated with the 066; do not use small differences between published figures to identify a saw.

The chain’s drive-link count depends on the bar length and mount. Do not order a chain based only on “3/8-inch pitch.” Check the bar stamp, chain stamp, and sprocket together.

How to verify a used 066 and its serial number

A serial number is an identification clue, not a universal year decoder. Number formats and available records can vary by market and production period. For a dependable identification, compare the number and model marking with STIHL or an authorized dealer, and inspect the parts fitted to the saw.

I use a simple cross-check before accepting a seller’s description:

• Find the serial number stamped on the saw’s body; its location can vary.
• Photograph the number and model marking clearly.
• Ask a STIHL dealer to check the number against available records.
• Compare the engine and parts configuration with the manual or parts information for the claimed version.
• Check whether replacement covers, handles, or other visible parts could explain a mismatch.

A badge is easy to replace, and used saws are often repaired over their lives. A genuine 066 may carry replacement parts, while a saw that looks like an 066 may not have the expected identity or configuration. A serial-number match is useful, but it does not replace an inspection.

Example: If a saw has an 066 cover but the seller cannot provide a readable serial number, do not treat the cover as proof of year or model. Ask a dealer to assess the identification and parts. If the seller’s claimed year conflicts with the available records, pause the purchase until the difference is explained.

Bar and chain setup for an 066

The right cutting setup depends on the saw’s condition, the approved equipment, and the work. Displacement alone does not determine a safe bar length. A longer bar raises engine load and kickback exposure, so use only lengths approved for the specific 066 configuration and keep the chain, bar, and sprocket compatible.

Before fitting cutting equipment, check:

• The chain pitch matches the drive sprocket and guide bar.
• Chain gauge matches the bar groove. Do not assume every 066 uses .063-inch gauge.
• The bar mount and drive-link count fit the saw and bar.
• Bar rails, nose, oil holes, and sprocket are in sound condition.
• Chain tension is correct according to the manual.

A 3/8-inch pitch chain can still be the wrong chain if its gauge does not fit the bar. Likewise, two bars of the same length may need different drive-link counts because of their mount or design. Read the stamps and confirm the combination before buying parts.

Bar oil flow and raker clearance depend on the setup and conditions. Use the chain maker’s filing gauge and the saw’s oil-flow check procedure rather than a single setting or flow figure found online. A dull chain or incorrect raker depth can make cutting slow and increase operator effort.

Equipment setup and safety preparation

A pre-start check helps catch faults before the chain moves. Wear a helmet, eye and hearing protection, chainsaw-protective legwear, gloves, and boots. Inspect the chain brake, throttle lockout, chain catcher, handles, controls, bar, and chain. Set a controlled work area and plan a clear retreat path.

Assess lean, decay, overhead hazards, wind, and the target area before cutting. Follow the applicable safety rules and training for the work. ANSI Z133 covers arboricultural operations; OSHA 29 CFR 1910.266 applies to covered logging operations. Use a qualified professional when the task or site exceeds your training.

Start the saw on firm ground with the brake engaged and the bar and chain clear. Follow the correct cold- or warm-start procedure for the model. At idle, the chain must stop. Stop and fix any chain movement, fuel leak, or brake or throttle fault before use.

Field cutting and operation

The 066 is a powerful, professional-class saw intended for demanding work, including large-diameter felling and bucking by trained operators. Good technique still matters more than engine size. Keep two hands on the saw, maintain stable footing, and avoid forcing the chain through the cut.

Hardwood can increase cutting load. Use a sharp, correctly matched chain and let the saw cut at its own pace. Do not cut above shoulder height, and do not continue with a dull chain. Both conditions make control harder and can increase risk.

Rotational kickback can occur if the upper quadrant of the guide-bar nose strikes wood or another object. The bar can move rapidly up and back toward the operator. Keep that area clear, avoid tip cutting unless trained and equipped for the task, and never use the saw with a defective chain brake.

Felling needs a planned notch and hinge and should be done only by trained operators when conditions allow. If the tree’s lean, decay, overhead hazards, or location make the fall uncertain, use a qualified arborist. Do not attempt a cut beyond your skill or the saw’s condition.

Maintenance, sharpening, and tuning

Routine checks help preserve performance and reveal wear before it becomes a failure. After work, clean the cooling fins, air filter, sprocket cover, and bar groove. Inspect the cutters, bar rails, chain tension, sprocket, and oil delivery. Follow the manual for service intervals and parts.

Use the chain manufacturer’s file size and filing gauge for the chain installed. The correct raker setting is chain-specific, so do not treat one measurement as universal. If the bar is unevenly worn or the nose is damaged, service or replace it according to the maker’s guidance.

For fuel, use fresh gasoline mixed at 50:1 with suitable STIHL two-stroke oil, unless the manual for that market or version specifies otherwise. Never run straight gasoline or an incorrect mix; inadequate lubrication can score the piston and cylinder or seize the engine.

Idle speed of 2,500 rpm and maximum no-load speed of 13,000 rpm are common published settings, but confirm the exact values for the saw’s manual. Use a tachometer for tuning. Do not tune by ear or exceed the specified maximum.

Storage and seasonal care

Store the saw clean, dry, and away from ignition sources. Before putting it away, engage the brake, stop the engine, and let it cool. Refuel only away from flames, sparks, or other ignition sources, and follow the manual’s instructions for fuel storage and longer-term storage.

Clean the bar groove and cover area, then check chain condition and oil delivery before the next use. On return to service, inspect the brake, controls, fuel system, and cutting equipment again. Do not assume a stored saw is ready to run simply because it worked before storage.

Frequently asked questions

What years was the STIHL 066 made?
The 066 is commonly documented as a 1986–2003 model. Production and availability dates could vary by market, so use a serial-number check and parts information to investigate a specific saw.

What model replaced the 066?
The MS 660 succeeded the 066. A change in model name does not prove that every part or version is identical, so check the correct parts information for the saw in question.

What is the displacement of a STIHL 066?
The commonly listed displacement is 91.6 cc. Confirm the saw’s identity and configuration before relying on that figure for a used or modified machine.

How much power does an 066 produce?
A commonly published figure is 5.2 kW, also listed as 7.1 bhp. Output figures can differ by version and rating convention.

Can I tell the exact year from the serial number?
Not reliably from a general online chart alone. Ask STIHL or an authorized dealer to check the serial against records available for that market and compare the result with the saw’s parts.

What fuel mix does the 066 use?
A common specification is 50:1 gasoline to suitable STIHL two-stroke oil. Follow the manual for the saw’s market and version, and use fresh, correctly mixed fuel.

Does every 066 use a .063-inch chain gauge?
No. A .063-inch gauge is common, but .050-inch configurations exist. Match the chain gauge to the bar groove and confirm pitch against the bar and sprocket.

What bar length should I use?
Use a length approved for the saw’s specific configuration and the work. A longer bar increases load and kickback exposure; check the manual and inspect the saw’s condition before fitting it.

What are the common idle and maximum speeds?
Commonly published figures are 2,500 rpm at idle and 13,000 rpm maximum no-load speed. Confirm the manual’s limits and use a tachometer for adjustment.

What should I check before buying a used 066?
Check the serial and model marking, have identification reviewed by a dealer, and inspect the engine, controls, brake, bar, chain, sprocket, and oil delivery. Do not rely on a badge alone.

(This article was written by one of our staff writers, Elliott Fowler. Visit our Meet the Team page.)