How do you start a flooded Stihl chainsaw?
Clear a flooded Stihl chainsaw by setting the master control lever to the run position with the choke off, holding the throttle trigger wide open, and pulling the starter rope repeatedly to burn off excess fuel. Flooding happens when too much fuel reaches the cylinder, usually from over-choking or repeated failed starts.
Work through these steps to clear a flood, in order:
- Engage the chain brake and set the saw on flat ground.
- Move the master control lever to the run position so the choke is off.
- Hold the throttle trigger fully open, using the trigger lockout as needed.
- Pull the starter rope firmly several times to draw air through and clear the cylinder.
- When the engine fires and runs, release the throttle and let it settle to idle.
If it still will not start, remove the spark plug with the correct tool, wipe it dry, and let the cylinder air out for a few minutes before refitting and trying again. Persistent flooding can point to a fouled plug, stale fuel, or a carburetor that needs a dealer's attention. Using fresh, correctly mixed fuel and following the proper starting sequence prevents most floods in the first place.
What causes a chainsaw to flood?
A chainsaw floods when more fuel enters the cylinder than the spark can ignite, most often from leaving the choke on too long or pulling repeatedly after the engine has already fired. Cold-start mistakes are the usual trigger, but a stuck choke or carburetor fault can also cause it.
Flooding is a fuel-air balance problem. Full choke deliberately enriches the mixture so a cold engine will fire; if you keep pulling on full choke after that first fire, or forget to move the control to the run position, raw fuel keeps loading the cylinder until the plug is too wet to spark. Repeated failed pulls compound it. Less commonly, a primer bulb pressed too many times, a sticking choke plate, or a carburetor that is out of adjustment will flood a saw even when the operator does everything right — those point to a service visit rather than technique.
How do you dry a flooded spark plug?
Dry a flooded spark plug by removing it with the correct socket, wiping it clean and dry, and letting the open cylinder air out for a few minutes before refitting. A visibly wet, fuel-soaked plug will not spark until it is dry.
The full process is short and worth doing carefully:
- Engage the chain brake and make sure the saw is switched off.
- Remove the spark-plug boot and unscrew the plug with the correct tool.
- Wipe the electrode dry; if it is sooty or badly fouled, clean or replace it.
- With the plug out, hold the throttle open and pull the starter several times to blow fuel vapor out of the cylinder.
- Let it air for a few minutes, refit the dry plug and boot, and try a normal warm start with the choke off.
If the plug is worn, cracked, or heavily fouled, replacing it is cheap insurance. A plug that keeps fouling after drying suggests stale fuel or an over-rich carburetor, which on a Stihl is best checked by the dealer.
How do you avoid flooding a chainsaw?
Avoid flooding a chainsaw by following the cold-start sequence exactly, moving off full choke as soon as the engine first fires, and using fresh, correctly mixed fuel. Most floods are caused by over-choking, so the fix is technique rather than parts.
A few habits prevent nearly all flooding:
- Move the control off full choke to the warm-start or run position the instant the engine fires once, then pull again to run it.
- Do not keep pulling on full choke; if it has not caught after the first fire, step the choke down.
- Use fresh fuel mixed to the ratio in the manual, since stale fuel starts poorly and tempts over-choking.
- Learn the exact starting sequence for your model and follow it the same way every time.
- Store the saw with stabilized or emptied fuel so it starts easily next season without extra choking.
Building the sequence into muscle memory is the real cure. Owners who flood a saw repeatedly are almost always over-choking out of habit; slowing down and moving off choke at the right moment eliminates it.
Always follow your model's manual, and keep the chain brake engaged throughout.
