Stihl Chainsaw Won't Start? Flooding and Fix Order

Quick answer

Most "dead" Stihls are one of two things: the Master Control Lever sequence done out of order, or a flooded engine from too many pulls on full choke. Cold start: throttle trigger squeezed while you push the lever down to full choke, pull until the engine fires once, immediately move the lever up one notch to half choke, pull again, and it should run. If the engine has already tried to fire and you've kept pulling on full choke and smell gas, skip straight to the flooded-engine fix below.

The cold-start procedure, exactly

Stihl's single Master Control Lever runs the choke, the starting throttle lock, and the on-off switch, and the sequence matters:

1. Engage the chain brake and put the saw flat on the ground. Left hand on the front handle, right foot toe in the rear handle.
2. Squeeze the throttle lockout and throttle trigger, and while holding them, push the Master Control Lever all the way down to the cold-start (full choke) position. The lever won't reach full choke without the trigger squeezed — this is the step that trips people up.
3. If your saw has a primer bulb, press it several times; it cuts down the number of pulls needed.
4. Pull the starter cord straight up with short brisk pulls — don't let it rake across the fan housing.
5. The moment the engine fires or "pops" once, move the lever up one notch to the half-choke position. This is the critical step: staying on full choke after that first pop is how Stihls flood.
6. Pull again — the saw should start and run at fast idle. Blip the throttle once to drop the lever to the run position.

Warm engine (it has been running for about a minute)? Skip the choke position and use the starting throttle position instead, then pull.

Flooded: the smell of gas and no fire

Pulling repeatedly after the engine has tried to fire, without moving the lever up, can flood it. Stihl's manual for the MS 210, 230 and 250 gives these steps for a flooded engine:

1. Set the Master Control Lever to STOP (0). Cranking with the plug out and the ignition live risks fire outside the cylinder.
2. Remove the spark plug and dry it.
3. Crank the engine several times with the starter to clear the combustion chamber. Keep sparks and flames away from the open plug hole.
4. Refit the plug.
5. Set the lever to the starting throttle position, even if the engine is cold, and restart.

If flooding keeps happening on textbook-correct starts, the carburetor's metering side or the plug is suspect, not your technique.

Fuel: fresh mix or don't bother

Stihl's manual for the MS 210, 230 and 250 specifies a 50:1 gas-to-oil mix using STIHL two-stroke oil or another high-performance oil it lists, and warns that a mix ratio that deviates from the specification can badly damage the engine. Other models can differ, so check the manual for your own saw. Mix left in the tank for months turns to varnish that clogs the carburetor and hardens fuel lines, and the manual says not to store mixed fuel longer than 30 days. If the mix in the saw is old, dump it, refill with fresh mix or canned premix, and pump the primer (if fitted) before blaming hardware. Check the in-tank pickup filter and the fuel line while you're there — a line cracked at the tank grommet sucks air and starves the carb.

Spark, air, and the exhaust screen

• Plug: pull it and look. Wet and black after failed starts means flooding or a rich fault; crusted deposits, a cracked insulator, or a worn electrode mean replace. Don't test for spark by cranking with the plug out; Stihl warns of fire risk from ignition outside the cylinder. If a new plug doesn't help, have a dealer test the ignition.
• Air filter: a cake of sawdust chokes the mixture rich. Tap it clean or wash per the manual; replace if torn.
• Spark arrestor screen: a carbon-blocked screen in the muffler will let a saw fire and refuse to run — a classic on saws that idle a lot. With the engine off and cool, pull the screen, brush the carbon off, or replace it.

Won't start hot

A saw that starts cold but refuses ten minutes after shutdown may be flooded, so follow the flooded-engine steps above. If hot no-starts become a pattern while cold starts stay easy, have a dealer inspect the saw.

Battery Stihls are a different checklist

If yours is an MSA-series battery saw, none of the above applies: check that the chain brake is pulled fully back (an engaged brake blocks the motor entirely), the battery is seated to the click, and the retaining latch is closed. Pack won't charge or flashes an error? Start with our Stihl battery charging guide. And if the engine runs but the chain won't move — gas or battery — that's the chain won't spin guide.