Stihl MS 250 Bar Not Getting Oil — Step-by-Step Diagnosis From Reddit

A Stihl MS 250 owner posted to r/Chainsaw with a problem that eventually affects every chainsaw: “My Stihl MS250 is dulling quickly and the chain is getting hot enough to smoke.” He had bar oil in the tank, but the oil was not reaching the chain. The bar was running dry despite a full reservoir.

This is one of the most common Stihl maintenance issues, and the fix is straightforward once you know where to look.

The symptoms

User u/wagoneer56 described exactly what to look for:

• Chain dulls after one cut instead of lasting a full tank
• Bar gets hot enough to smoke — you can see wisps rising from the bar nose
• When revving the saw over a light surface, there is little or no oil spray from the chain tip
• The bar oil he ran for a few seconds was “absolutely filthy” — dark and full of wood pulp

All four symptoms point to the same cause: the oil delivery path is blocked.

The fix: clean the oil path (20 minutes)

u/CountMC10 gave the top-voted answer, and it is the correct diagnostic sequence:

Step 1: Clean the bar groove

Remove the chain and clean the groove channel around the entire bar edge. Use an old hotel key card, a credit card, or a flat screwdriver wrapped in cloth. The groove accumulates compacted sawdust and pitch that restricts oil flow to the chain.

Step 2: Clear the bar oil port

Every Stihl bar has a small oil inlet hole near the mounting slot. On the MS 250, it is on the inside face of the bar, near the bottom of the mounting area. Use a thin wire or needle to clear any debris from this hole. If this port is blocked, oil cannot enter the bar groove regardless of how well the pump works.

Step 3: Clean the drive sprocket area

Remove the bar entirely and clean the area around the drive sprocket and clutch drum. Sawdust packs into the oil outlet on the powerhead — this is the exit point from the oil pump. If this is clogged, oil backs up in the pump and never reaches the bar.

u/knuckle_headers added: “If you have access to an air compressor with a blowgun attachment — that is the quickest way to blast the packed sawdust out.”

Important warning from u/Priff: “Do avoid hitting the oil hole on the saw with compressed air though. The back pressure can damage the oil pump.”

Step 4: Check the oil pump output

After cleaning, reassemble the bar and chain, fill the oil tank, and run the saw at full throttle while pointing the bar tip at a clean piece of cardboard. You should see a fine line of oil sprayed onto the cardboard within 10 seconds. If there is no spray, the oil pump itself may need replacement — but this is rare. 90% of “bar not oiling” cases are resolved by cleaning.

When cleaning is not enough

If the oil path is clear but oil still is not flowing:

• Oil pump worm gear — on the MS 250, the oil pump is driven by a worm gear off the crankshaft. If this gear is stripped (common after 5+ years), the pump spins but does not push oil.
• Oil line — the small rubber line from the tank to the pump can crack or collapse, especially on saws stored for long periods.
• Oil adjustor screw — the MS 250 has an oil flow adjustment screw on the bottom of the saw. It may have been accidentally turned to minimum. Turn it counterclockwise to increase flow.

Why this matters for your bar and chain

Running a saw with insufficient bar oil does not just dull the chain faster — it damages the bar. The heat generated by dry friction:

1. Widens the bar groove unevenly, causing the chain to wobble and cut crooked
2. Hardens the rail edges past their operating spec, making them brittle
3. Burns the bar nose sprocket bearings, causing the tip to seize

A ruined bar means replacing both the bar and chain as a matched set. If you catch the oil flow problem early (before the bar shows heat discoloration), cleaning the oil path saves you $40-80 in replacement parts.

For more on bar condition assessment, see our guide: When should you replace your chainsaw guide bar?. If you do need a replacement, browse our Stihl-compatible bar and chain combos.

Maintenance schedule

To prevent oil flow blockages:

• Every fill-up: Check oil level, wipe the bar mounting area
• Every 3 tanks: Remove the bar, clean the groove with a card, clear the oil port
• Every season: Inspect the oil line and pump output, clean the sprocket area thoroughly, flip the bar to even out rail wear

This 5-minute routine between fill-ups is the single most effective thing you can do to extend bar and chain life. The MS 250 is a legendary homeowner saw — with proper oil flow maintenance, the bar should last 3-5 years of regular firewood cutting.