Stihl MS 390 Used Saws (Buyer’s Guide)

A used MS 390 can suit routine bucking and felling when it is mechanically sound and correctly matched to the work. Before buying, verify the model, inspect safety parts and engine condition, and confirm the bar and chain fit. Do not judge value by the badge alone: repairs, wear, and local prices matter.

The costly mistake is choosing by engine size or a seller’s claim that the saw “runs great.” A chainsaw may start and still have a worn sprocket, weak oil delivery, or a faulty chain brake. Those faults can turn a tempting deal into a repair bill or an unsafe tool.

I use a simple rule when assessing an older saw: prove its identity, check its safety and cutting setup, then judge its engine and price. The MS 390 has a 64.1 cc engine, but condition and correct setup matter more than displacement alone. Treat any saw with an unresolved safety fault as a no-buy until a qualified technician checks it.

What the MS 390 is suited to

The MS 390 is a 64.1 cc saw intended for substantial cutting work. A sound example can suit routine bucking and felling in trained hands. Its size does not make every tree or bar length a good match; wood, saw condition, and operator skill all affect safe use.

For general work, a sound 16- to 20-inch bar is a practical starting range, provided the saw’s manual and installed parts approve the setup. A longer bar puts more load on the engine and operator. Dense hardwood, large stems, and long-bar cuts need careful planning. Do not force the saw through a cut.

The published figures below are useful for checking a candidate, but manuals and parts can vary by market or version. Confirm the exact saw’s manual and component markings before buying parts or tuning.

Takeaway: A good match is a healthy saw with an approved bar and chain for your actual work, not the longest bar the seller can fit.

Inspect a used MS 390 before paying

A used-saw inspection checks identity, wear, safety controls, and visible signs of engine or fuel trouble. It cannot replace a proper service assessment, especially when compression, carburetion, or internal engine condition is uncertain. Inspect the saw cold if possible, and ask the seller to demonstrate a safe start and idle.

Confirm the saw and cutting parts

Read the model and serial markings, then compare them with available model information and the correct manual. Check that the bar, chain, and sprocket agree on pitch, and that the chain gauge matches the bar. Count drive links if you are confirming replacement-chain fit. A mismatch is not a minor detail: it can prevent correct fit or safe operation.

Inspect the bar rails for uneven wear, damage, or spreading. Look at the nose and sprocket nose for damage, and check that the chain moves freely when the brake is released. The chain should tension correctly without binding. Examine cutters for damage and uneven sharpening.

Look at the drive sprocket for wear and inspect the clutch area for damage or heavy debris. A worn sprocket can accelerate chain wear. Ask when the chain, bar, and sprocket were last replaced, but treat the answer as a claim, not proof.

Check safety parts and condition

Engage and release the chain brake, check the throttle lockout and stop switch, and inspect the handles and anti-vibration mounts for damage or looseness. Look over the crankcase, fuel tank, caps, and fuel lines for cracks, leaks, or signs of repair. Check that the chain catcher and other fitted safety parts are present and secure.

With the saw at idle, the chain must not move. If it does, stop the inspection and do not use the saw until the cause is fixed. Ask the seller to demonstrate chain-oil delivery using the manual’s method. Never assume the automatic oiler works just because the reservoir is full.

A start-up alone does not prove good compression or sound fueling. If the saw is hard to start, stalls, races, leaks fuel, or runs unevenly, ask a qualified service provider to assess it. Do not buy on the promise that a suspected lean-running problem “just needs tuning.”

Takeaway: Walk away from unresolved brake, throttle, stop-switch, fuel-leak, or oil-delivery problems. Price an engine or fueling concern only after a technician diagnoses it.

Match the saw, bar, and work safely

This section helps you decide whether a particular MS 390 setup suits your job. Bar length, chain pitch, and gauge must agree with the saw’s approved parts. Good technique and protective equipment matter just as much as the saw’s condition, especially during felling.

Use the right setup and fuel

Use fresh fuel mixed at 50:1 with approved two-stroke oil, following the manual and oil maker’s guidance. Never use straight gasoline or an incorrect mix; poor lubrication can cause severe engine damage. Use proper bar-and-chain oil, and check delivery before cutting.

The chain pitch must match the sprocket and bar. Gauge is the chain’s drive-link thickness and must match the bar groove. Common MS 390 bar setups may use .050- or .063-inch gauge, but confirm the markings on the actual parts. Never mix gauges or assume that a chain advertised for the model fits every bar.

Sharpen to the chain maker’s file size and angles. Set depth gauges, which control how much wood each cutter bites, to that chain maker’s specification. A .025-inch (0.65 mm) setting is common, not universal. Replace cracked or badly worn chain parts rather than trying to sharpen them back into service.

Prepare, start, cut, and finish

Before starting, check PPE, controls, chain tension, bar and chain fit, fuel, oil, hazards, escape routes, and a way to communicate. Wear fitted chainsaw leg protection, a helmet with eye or face and hearing protection, gloves, and suitable boots. Follow applicable worksite rules, including ANSI Z133 and OSHA requirements where they apply.

Start on stable ground with the chain brake engaged and follow the correct manual for a cold or warm start. Do not drop-start. Once running, confirm the idle is steady and the chain remains still. For service checks, use the manual and a tachometer; do not tune maximum speed by ear.

Keep two hands on the saw and a secure stance. Where practical, cut with the lower part of the bar, and plan how the wood may move as the cut closes or releases. Avoid the upper quadrant of the bar nose: contact there can cause rotational kickback toward you. The chain brake helps, but does not make kickback harmless.

For felling, plan a directional notch and a controlled back cut that leaves adequate hinge wood. Never cut through the hinge. Set an exclusion zone and escape routes before the tree comes down. Under OSHA 1910.266, logging work requires at least two tree lengths between workers while trees are being felled. Never cut above shoulder height or force a dull chain.

After cutting, engage the brake and shut down. Let the saw cool in a safe place, then clean debris from the clutch cover, cooling areas, air-filter area, and bar groove. Recheck chain tension and oil delivery before the next use.

Takeaway: If the work calls for a longer bar, difficult wood, or felling beyond your training, reassess the saw and the plan rather than pushing the MS 390 harder.

Used-saw buying scenarios, maintenance, and value

These examples are inspection scenarios, not reports of specific sales. They show how I weigh condition against intended use. A local price comparison is more reliable than a fixed online estimate because asking prices, parts, and repair costs vary by place and time.

A useful used-saw price is not simply the lowest asking price. Compare similar local listings, then account for confirmed parts and labor needed to make this saw safe and reliable. If the seller will not allow a basic inspection or safe demonstration, the uncertainty itself is a reason to pass.

For routine care, clean the air filter as directed and inspect the spark plug and fuel lines. Clean the bar groove and oil holes, and inspect the rails and nose. Do not run with a dry chain or raise engine speed to make up for poor lubrication. Carburetor settings vary by model and condition; suspected lean running or abnormal top speed needs a manual-based, tachometer-guided service check.

For long storage, follow the manual’s fuel-system directions. Drain or stabilize fuel only as directed, and run the saw only if the manual says to. Clean and protect the bar and chain, and keep stored fuel in an approved container.

Takeaway: Make your offer after you know what needs repair. If critical safety or engine questions remain unanswered, choose a better-documented saw.

Frequently asked questions

Is a used MS 390 worth buying?

It can be, if its safety parts work, its engine condition is acceptable, and its price reflects any needed repairs. Have a technician assess unresolved engine or fueling concerns before purchase.

What bar length should I use on an MS 390?

A sound 16- to 20-inch bar is a practical general-purpose match. Use only a bar approved for the saw, and confirm the chain pitch and gauge match the bar and sprocket.

What fuel mix does the MS 390 use?

The published mix is 50:1 gasoline to approved two-stroke oil. Confirm the manual for your saw and use fresh fuel. Never run straight gasoline in this two-stroke engine.

What chain pitch and gauge does it take?

The pitch is 3/8 inch. Gauge depends on the bar; .050 and .063 inch are common. Read the bar and chain markings, and do not mix gauges.

How can I tell if the chain oiler works?

Use the check described in the saw’s manual and confirm that oil reaches the chain and bar. A full reservoir does not prove oil is flowing. Do not cut with a dry chain.

Is a saw that starts automatically a good buy?

No. Starting is only one check. Inspect the brake, throttle lockout, stop switch, mounts, fuel system, chain, bar, sprocket, and oil delivery, and seek service help for uncertain engine condition.

What should I do if the chain moves at idle?

Do not use the saw. A chain that moves at idle needs diagnosis and repair before operation. Have a qualified service provider check it, then confirm the chain stays still at idle.

Can I use a longer bar for large trees?

Only if the specific bar and saw combination is approved and the work calls for it. A longer bar increases load and operator demand. Do not force the saw through dense or large wood.

Should I tune the carburetor by ear?

No. Use the correct service manual and a tachometer, or have a qualified technician do the work. Abnormal speed or suspected lean running can damage the engine.

What is the safest reason to pass on a used saw?

Pass if a critical safety control is missing or faulty, fuel leaks, oil delivery is unproven, or the seller will not allow a safe inspection. Resolve those issues before use, not after cutting.

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