Stihl Chainsaw Won't Start - The Reason Why Surprised Me

My Stihl chainsaw would not start. I changed the fuel, checked the spark plug and more. The reason why surprised me.

[salomonponce]

You make my day with this advice; I spend many hour trying to find the reason my stihl chainsaw won’t start, so I replaced the gas, and works like magic! Definitely Stilhl’s doesn’t like old gasoline! 😅

[KristenKruse]

Stihl Farm Boss would not start for nothin' the other day.( I had not used it since last year). Dumped out fuel and refilled with the fuel I mixed last year. Still no luck! I dumped out that fuel and purchased fresh, TruFuel 50:1 in the can and voila! after 3 or 4 pulls, the saw started up and is running like a champ! Had no idea the saw is that sensitive to stale fuel. Thanks for posting this video!

[lighthousei]

A few things:
1) When checking the spark plug for spark, it has to be "grounded" so make sure the threads are contacting metal.
2) It's not a bad idea to purchase a quart of 50:1 gasoline when trouble shooting, which should rule out stale gas.
3) I also have the MS290 & it floods easily. Sometimes I don't even need to use the choke, even if I haven't used it in months. So if it won't start, you might have flooded it at full choke, so set it to "ignition" (no choke at all), engage the brake, pull in the trigger, press your knee against the top of the chainsaw to secure it to the ground & start pulling on the cord. It might take 20 or more pulls but if it's flooded this will do the trick.

[luke]

I had the same problem and took mine to the local hardware mechanic the next day. It started right up for him. He told me after these saws set for a long period of time the diaphragm in the carburetor can dry out. But after attempt of starting and letting it sit for an hour or two it would start no problem

[bunberrier]

Thanks. I picked one of these off the curb on my weekly "trash patrol". I find all kinds of stuff. The week before that was an antique bench grinder that just needed a new cord. Anyway I already verified spark and spark plug, compression, and clean filter. The fuel in it smelled janky so especially after seeing your results I'll swap that out next.

[jchuhn]

Thank you my friend. My problem was the same as yours. I dumped the old gas and refueled with True Fuel 94 octane and it brought the saw back to life.

[ScaleRacingChannel]

Always check the exhaust ports for mud dauber nests. I've had my fair share of no starts from that reason alone, while living in TN.

[BlackMan]

Jesus… my MS271 wouldn’t start on the day I bought it! It’s been hard to start ever since and is not even a year old. I am really starting to doubt Stihl at this point. I started using my 25 year old one!

[gusr]

Thanks for posting this video. I've been using decent fuel and still having occasional problems starting my farm boss. After watching your video I poured the fuel out from the saw into a clean white container and I was shocked by the bits of black crap that were sitting in the bottom. I've given it a decent flush and problem is now solved.

[lancehughes]

I've got a new 271 and it's a bear to start. Yes, place it on the lower setting til it burbs, then move to the next notch up; still (Stihl) hard to start ! Can also be hard to turn over when it sits for a few months. Now onto starting with the 'chain brake' on. You can forget it. It will not rev up and quickly stalls. In addition, no design should be so fuel finicky. Let me know if you're having similar problems.

[ArrowItArchery]

TruFuel or VP Racing, 50-1mix in the can. They're ethanol free, with a 2 year shelf life after opening the can, and a 5 year shelf life if unopened. It's pricier, but worth it if you rarely use the small engines. You don't have to winter-prep with this fuel, meaning you don't have to empty the tank and run it dry. It won't break down. If you keep something running often, then fuel station gas will be ok. When it's getting close to the season where the machine wont be used for a good stretch, I'd switch over to the TruFuel and run through a tank or two on the last tasks, so it's in the carbs for the lengthy storage. You'll thank me later for this. 😁

[williambennett]

Don, t dispose of old fuel, its ideal for cleaning away oil dirt, cleaner in ultra sonic device in sealed container, brush cleaner, fire starter would you believe, and Molotov cocktails.

[anthonyhro]

Every time I get my STIHL out, first thing I do is put on my JOCK STRAP. They are a pain to start!

[robertpizeljr.]

Great job with you maintenance diagnostics! Just a small tidbit, always add SEAFORM additive to your 91% octane gasoline or higher fuel used.

[fisherguy]

I always use Chevron 94 for my small motors and never had a problem with carbs gumming up etc. 94 was ethanol free until 2-3 years ago up here in Canada.
This past spring I had a helluva time getting my 362 started and it's been sitting for 4 months since then and again it wouldn't start. Found this video and figured it was worth a try.
Some fresh 94 and Stihl oil, didn't start in choke mode, turned to run and after about 6 yanks it fired up, success! Stange it didn't fire when choked buy at least I'll be able to get firewood on our fall fishing trip.
Thanks for your video. 👍👍

[mikegrant]

Another thing to watch out for on some Stihl saws is the ground wire routing that can wear off the insulation and cause an intermittent shorting. As it slowly erodes the ground wire it becomes more frequent. Easy to check and easy to repair with a bit of electrical tape or liquid tape stuff. Just follow the wire and examine it closely. If you see any open wire, fix it. Why the Stihl engineering group decided to route it behind something that can vibrate was probably an oversight but it can be maddening to discover, thinking it's a coil going bad or the carburetor out of its proper range.

[mydoggone]

Thanks for the advice…I tried to start mine for over an hour with no luck watched this video and changed the gas and third pull she started 😅

[juniorboyd]

Number 1 - spark plug. If I’m not going to be using my saw for several months. I empty all the fuel out and run the saw until all fuel is through the lines and allow saw to die. The carb and lines will gunk up if your running ethanol. Anytime your using mixed oil and it’s been sitting ALWAYS mix it good shaking from side to side. Every 100 hours new spark plug. I bought a “ newish “ Ms251 and still tinkering with it.

[ab_ab_c]

Once you get the saw running hot on new fuel, you can use the old fuel in the saw.
No need to toss it out unless the fuel is very old or it has too much water in it.

[rays]

Flannel, I have a Stihl mini tiller with the same engine you are working with here and I can not get it to even fire. I can rebuild this entire engine by myself and have no hesitations as far as my ability to do it correctly. I rebuilt the carburetor and it was spotless on the inside, not one spec of dirt or debris. I am getting somewhere around 140 PSI compression. I am getting a very strong spark and the spark plug is brand new and putting out a dark blue spark. I even took the flywheel off to make sure the shear pin was not sheared off and the timing being the culprit and no such luck. I've shot carb cleaner gas and brake cleaner in the carb and once again can not even get it to fire. I tried brand new Stihl 2 cycle fuel from a Stihl dealer and still nothing. The primer bulb is working properly and filling the chamber as it should. I think I about covered everything. Got any ideas?