Stihl MS 271 and MS 261 Chainsaw Fixes: Starting, Oiling and Carb

To start a Stihl chainsaw: engage the chain brake, set choke to full (cold start), press the decompression valve if equipped, pump primer bulb 3-5 times, hold the saw firmly and pull until it pops. Move choke to half, pull again until it starts, then push choke in fully. Cold starts take 3-6 pulls. The MS 271 Farm Boss (50.2cc, 3.49 HP) and MS 261 (50.2cc, 4.0 HP) use the same starting procedure.

These Stihl saws are tanks—I’ve seen 271s with 15 years of hard use still cutting. But they’re not bulletproof. Most problems come down to fuel issues, oiler problems or user error on the starting procedure. Let’s sort out what’s going on with yours.

MS 271 vs MS 261 Comparison

Feature	MS 271 Farm Boss	MS 261
Engine	50.2cc	50.2cc
Power	3.49 HP	4.0 HP
Weight	12.3 lbs	10.8 lbs
Bar Length	16-20”	16-20”
Best For	Homeowner/Farm	Professional light

[NEED REAL IMAGE: Stihl MS 271 showing controls and features]

Both use similar components. The MS 261 adds advanced features for professional use.

Won’t Start Fixes

Won’t Start Cold

Proper cold start procedure:

1. Set choke to full (cold start position)
2. Set master control to start
3. Prime if equipped (decompression valve)
4. Pull until first pop
5. Move choke to half
6. Pull until running
7. Move choke to run

If still won’t start:

1. Check fuel freshness (50:1 mix, under 30 days)
2. Inspect spark plug
3. Verify fuel reaching carb (prime bulb fills)
4. Check air filter

Won’t Start Hot

Hot starting:

1. No choke needed
2. Master control to run
3. Pull 2-3 times

If won’t hot start:

1. Flooding - wait 5 minutes, try with throttle open
2. Vapor lock - let cool, try again
3. Carburetor issue

Pulls Hard or Won’t Pull

Possible causes:

1. Hydro-lock (fuel in cylinder) - remove plug, pull several times
2. Starter clutch/spring broken
3. Piston/cylinder damage (rare)

Starts Then Dies

Common causes:

1. Carburetor needs adjustment - see Zama carburetor repair
2. Fuel filter clogged
3. Air leak at intake
4. Spark arrestor plugged

Engine Problems

Engine Surges

RPM hunts up and down:

1. Carburetor needs tuning
2. Air leak at gaskets
3. Fuel delivery restriction
4. Governor/limiter caps need adjustment

Lacks Power

Engine runs but weak:

1. Dull chain (most common)
2. Air filter restricted
3. Spark arrestor clogged
4. Exhaust port carbon buildup
5. Low compression

Check compression: Should be 150-180 PSI. Below 120 indicates problems.

Overheating

Engine runs hot:

1. Air filter clogged
2. Cooling fins blocked
3. Fuel mixture too lean
4. Running too long at full throttle without load

Smoking Excessively

Blue/white smoke:

• Too much oil in mix (check 50:1 ratio)
• Poor quality oil
• Worn rings/piston

Black smoke:

• Running rich
• Choke stuck
• Air filter clogged

Oiler Problems

Chain Not Getting Oil

MS 271/261 use automatic oiling:

Check:

1. Oil tank has bar oil
2. Oil pump working (see below)
3. Bar groove clean
4. Chain oiling holes open

Oil pump test:

1. Remove bar and chain
2. Start saw, rev to medium
3. Look for oil spray from pump outlet
4. No oil = pump problem

Oil Leaking

Leaks from bottom:

1. Oil cap o-ring damaged
2. Oil line cracked
3. Tank seam failure

Leaks only when stored:

• Temperature changes cause pressure changes
• Normal for some oil seepage
• Major leaks indicate seal failure

Adjusting Oil Output

MS 271 has adjustable oil pump:

1. Locate adjustment screw (bottom of saw)
2. Turn clockwise = less oil
3. Turn counterclockwise = more oil
4. Bigger bars need more oil

Chain and Bar Problems

Chain Comes Off

Causes:

1. Chain tension too loose
2. Bar rails worn
3. Drive sprocket worn
4. Chain stretched beyond service life

Proper tensioning:

1. Loosen bar nuts slightly
2. Turn tensioner clockwise to tighten
3. Chain should pull freely but not sag
4. Tighten bar nuts

Chain Won’t Cut

Dull chain signs:

• Sawdust instead of chips
• Have to push hard
• Smoke from cut

Sharpening needed - file or grinder service.

Bar Problems

Bar rail wear:

• Chain wanders in cut
• Uneven rail height
• Replace bar if rails worn

Bar nose sprocket:

• Grease fitting needs regular attention
• Frozen sprocket = replace bar

Chain Brake Issues

Brake won’t engage:

1. Brake band worn
2. Spring broken
3. Linkage bent

Brake won’t release:

1. Reset procedure not followed
2. Brake band stuck
3. Mechanism damaged

Carburetor Problems

Understanding Stihl Carburetors

MS 271/261 use Zama carburetors with limited adjustment (EPA compliance). See our carburetor cleaning guide for general carb service steps.

Adjustment screws:

• L = Low speed mixture
• H = High speed mixture
• LA = Idle speed

Limiter caps restrict adjustment range to meet emissions standards.

Carburetor Adjustment

Basic procedure:

1. Start saw, warm up
2. Adjust LA for proper idle (chain shouldn’t move)
3. Adjust L for clean acceleration
4. Adjust H for maximum power without four-stroking

For access beyond limiters: Remove caps (voids emissions compliance) or see Stihl dealer.

Carburetor Rebuild

When needed:

• Won’t adjust properly
• Diaphragms hardened
• Leaking fuel

Rebuild kit: $15-25

Carburetor Replacement

When rebuild fails:

• Body corroded
• Throttle shaft worn
• Multiple failed attempts

Replacement cost: $45-75

Maintenance Schedule

Every Use

• Check chain tension
• Check oil level
• Inspect chain sharpness
• Check air filter
• Verify chain brake function

Every Tank of Fuel

• Clean air filter
• Check bar for wear
• Flip bar for even wear

Every 10 Hours

• Clean spark arrestor
• Check spark plug
• Clean cooling fins
• Grease bar nose sprocket

Annually

• Replace fuel filter
• Replace air filter
• New spark plug
• Inspect fuel lines
• Check starter rope

Replacement Parts

Part	Stihl Part #	Cost
Air filter	1141 120 1600	$12-18
Spark plug	0000 400 7011	$6-10
Fuel filter	0000 350 3510	$5-8
Chain (16”)	Various	$20-35
Bar (16”)	Various	$40-60

When to Get Professional Stihl Service

DIY appropriate:

• Chain sharpening
• Air filter cleaning
• Spark plug replacement
• Basic carburetor adjustment

Dealer recommended:

• Carburetor rebuild/replacement
• Oiler pump repair
• Compression issues
• Chain brake service
• Ignition problems

Frequently Asked Questions

MS 271 vs MS 261 - which should I buy?

MS 271 Farm Boss for homeowners and occasional use. MS 261 for professionals or heavy users wanting lighter weight and more power.

How long do these saws last?

With proper maintenance, 10-20+ years for homeowner use. Professional use may see 3-7 years of heavy service.

Can I run E10 gas?

Yes, but use Stihl fuel stabilizer. Better yet, use ethanol-free gas or Stihl MotoMix.

Why does Stihl limit carburetor adjustment?

EPA emissions regulations. Dealers can access full adjustment for tuning.

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Stihl’s MS 271 and MS 261 are proven workhorses. Keep the chain sharp, air filter clean and use fresh fuel for years of reliable cutting.