How to clean a plugged exhaust screen - spark arrestor on a Stihl Weedeater (if it's bogging)

Here is a quick video showing how I like to clean the exhaust screen / spark arrestor in my Stihl 2 stroke weedeater / line trimmer. The model in this video is the FS 55 R but this guide applies to just about any machine out there, fs 36, fs 38, fa 40, km, km90, km110, km110r, (kombi) that has an exhaust screen in the muffler, blower, trimmer, brushcutter, etc. If your weedeater bogs and wont rev, is hard to start, or won't start, and is also very quiet than you are used to, chances are it's a plugged exhaust screen / spark arrestor. A bogging weedeater is no fun, try this!
#smallenginerepair
#landscaping

[@roughcutscanada]

Thank you for this video. I was just about to take my Stihl FS55 to the dealership for service. The issue was exactly as your video showed. You sir, just saved me $$. Thank you!

[@israelvazquez3062]

They don't charge much.. it's just the waiting time that's sucks

[@stevemittelman4068]

Nicely done. No diversional music or intro. Right to the point. Thank you ! Bravo!

[@machinesnmetal]

Glad you liked it!

[@kevincurtis9404]

Your video was spot on perfect! My weed whacker now works like a charm. And you saved me a trip to the repair shop. Thank you so much.

[@machinesnmetal]

You! Are the mechanic now

[@wrenchy3781]

2 different Stihl dealers told me my FS40 needed a carburetor, $50 bucks, i took carb off and cleaned it up and i could not believe any thing wrong with carb, hated the idea of trashing this Stihl Weedeater. as usual i turned to youtube and watched this video, i took one screw out of muffler and the screen was clogged w/carbon, i used a torch and compressed air and weedeater runs like new ! Thank You for saving me $50 and more importantly my Weedeater ! I hope Good Fortune heads your way my American Friend !

[@machinesnmetal]

Im sorry, Im canadian

[@angelossakellariou2832]

machinesnmetal Still in America 😊

[@susanr9057]

Hey Machinesnmetal, I don't know your real name, but I want to say thank you. Because of your very clear and precise video, with all the information I needed, this 68 year old old lady was able to fix my Stihl weed whacker this morning. The most important thing you mentioned was what size socket I would need, I had to borrow one of those from a neighbor, I only have inch sockets. So, thank you so much for replying to my questions so that I could fix my Stihl and still feel useful. Your biggest 68 year old fan. Susan

[@mrpawpaw7023]

Thank you for this video. This was exactly what was wrong with my trimmer which I was nearly ready to throw in the trash. I even bought a battery trimmer to replace it. I did not need to use a blower. The screen burst into flames when heating it since it was covered with so much gunk and everything burnt off.

[@TonyPuryer]

Great video. Just a tip with the flame - pull back a bit, the hottest part is at the tip of the bright blue inner flame. Thanks for sharing!

[@plowman1266]

paid someone to edge last year weed eater was running bad. spring here i changed carb and was gonna order a clutch… saw your vid in 10 minutes runs like new.. my hero

[@machinesnmetal]

You are the mechanic now!

[@jimamccracken5783]

Just a quick thanks. My stepson was using my FS 40and noticed a severe drop in power. So we looked at you page and behold the answer was SPARK ARRESTER. I bought this machine in 2015 and had never cleaned it. Silly me however we took the screen out and wired brushed it really good. Now she is running like new. Thanks for the info.

[@CahorePt]

Awesome video! I've now fixed 3 garden tool engines at home that were clogged. After doing this they went from almost no power to full power.

[@machinesnmetal]

Nice work, you are the mechanic now!

[@ericbaker3435]

Thank you, thank you, thank you! I was getting ready to buy a new FS56, but you just saved me $220! Awesome video!

[@machinesnmetal]

You are welcome!

[@garywheeler2055]

Very “to the point” presentation. I wish everyone did it this well. 👍

[@machinesnmetal]

Thanks!

[@zacksupal6711]

Super helpful! Was about to chuck mine in the bin. Did this and wow its like a new trimmer again!

[@machinesnmetal]

yay!

[@smallengines1018]

What model was it?

[@bruceknight878]

@@smallengines1018 ml

[@johnhale5271]

Great info. Thanks for the video. Replaced the carb unnecessarily. SA was clogged. Will run a little less oil from now on.

[@rbhug21]

Wow!! This worked great! Had an FS45 that was running the same way. Now runs like new. Now I’m yanking the spark arrestors out of my other Stihl equipment and doing the same thing. Thanks!!

[@jeffreymaurits6948]

Thank you.... replaced carb, plug, fuel lines, fuel filter, etc... still wouldn't stay running... gave up and found your video and found that the exhaust screen was my issue! Followed your suggestions and weedeater runs like new!

[@machinesnmetal]

You are the mechanic now!

[@turpinglipper9171]

I followed your vid, fixed my line trimmer. Thanks, you saved me money and time.

[@guycrider839]

You just saved 3 stihl trimmers lives thanks

[@dhuebner6471]

Thanks! Mine was doing the same thing. Watched your video and followed your instructions. Works as good as new.

[@beaznuts]

Bought a used trimmer - started to think i got ripped! Looks like it was a good deal now!!! Cheers!

[@TireShredder]

I have been soaking mine in combustion chamber for a week and it looks the same. Gonna try this! Thanks! FYI my machine is 11 years old and always had the right mix of stihl/Castrol oil. I think part throttle makes it happen faster, as my blower spark arrestor is still really clean.

[@darrenparkin3090]

Very helpful video, almost ready to drop my stihl FS38 off at dealer and this worked like a charm.

[@johnhayes4142]

Timely advice. I was just about to replace the carburetor after many frustrating attempts to tune my FS55. After this she's purring like a kitten, just like new. Buzzer, Ballina, Australia

[@machinesnmetal]

Radical!

[@borishruskar5108]

Very nice and usable video. I had same problem and I resoved it because of advice from this video. Thanks for this.

[@machinesnmetal]

Glad it helped

[@tonykhairy9791]

Thank you mate I owe you a beer if you ever swing buy to Sydney . This is an excellent help

[@machinesnmetal]

I'm just north of you in Moalboal Cebu this winter 😊

[@bryanr9528]

Great information, Thank you. I would like you to see how to clean and degrease the unit.

[@gmtv9928]

Very helpful! Thanks for taking the time to share it..

[@machinesnmetal]

Thanks for watching!

[@magreger]

Thank you for sharing! My FS 55R runs like brand new again! This was cheaper and faster than using all those cans of carb cleaner and brake clean I've been using over the years lol.

[@machinesnmetal]

Some people swear by brake kleen, some wire brush, thanks for the kind words fellow torch enthusiast!

[@hjsdshabdhgadhfgadhf]

Great video. Easy and to the point, thanks for sharing.

[@machinesnmetal]

Glad it was helpful!

[@susanshelton8004]

Old school for sure, carb cleaner cleans excellent and so much faster

[@machinesnmetal]

Ultrasonic or the spray can type?

[@MattGipson-xw3gu]

Thanks for sharing. It helped me fix my trimmer! But I gotta say, y’all must have a thing for the torches cause it’s totally not required. I used a SS wire brush and cleaned my arrestor grill in about 5 min. Trimmer fired right up.

[@machinesnmetal]

I LOVE torches. I don't like to use a wire brush as I find in my experience it scratches the material the screen is made from and thus carbon sticks to the scratches and it builds up faster than the first time.

[@bikeblokes]

Thanks mate, fixed my unit.

[@suenewton3684]

Wow amazing and informative! Thanks

[@AlexanderTheGrateful]

I just checked mine after 15 years of use, and mine is clean as a whistle, I never let small two stroke engines idle, I start them up and full throttle and switch it of between sections, and Its still going strong

[@dalehammond1749]

My Stihl FS 55 RC is very different. Mine must of been an experimental model? It has a stainless steel plate over the muffler outlet and the entire housing front and back have to be removed to service the spark arrestor (evidently).

[@aischaparker9471]

Great video, thanks so much, u just saved me $150 cos now i can fix mine myself. Bless you

[@madasyk1]

Thank you for this information. Very helpful.

[@dnomyarnostaw]

Well done. Worked for me like a charm.

[@machinesnmetal]

I'm glad to hear it was helpful

[@Back2TheBike]

Greetings from the UK. No good for me as my unit has the solid metal exhaust, no access to the mesh. I had this problem on my Stihl FS55 strimmer. .Solved it by giving the inside of the exhaust with a good dose of carb cleaner,shook it around for a few mins, rinse - repeat - worked perfectly! Let it dry out before firing up though 🔧as it's flammable.

[@machinesnmetal]

I had a similar problem with an old 2 cycle golf cart muffler. It was completely plugged solid with 2 stroke "tar" I removed it from the cart and put it into a barbeque for 5 hours, roasted all the tar out, ran as good as new afterwards.

[@thomascrosby6105]

no torch or compressor. mineral spirits, acetone, degreaser, old toothbrush, dip, lightly scrub, took 10 min blew on it ,clear, screwed it backl in, works like new. thanks for insight

[@johnnycurley3225]

Thanks helped me

[@rjetti11]

Is their anyway to clean the screen if you don’t have a torch.

[@machinesnmetal]

Not in my experience, you could order a new screen from your Stihl shop. Get a couple-

[@kenjohnson5498]

Try running "Red Armour" 2 cycle mix through it, it will clean it out and keep it clean as long as you don't over mix.

[@machinesnmetal]

Shindaiwa Red Armour in my opinion is the best 2 cycle mix on the market.

[@Nzchimeran]

😊legend, exactly what was wrong with mine. Thank you

[@machinesnmetal]

You are the mechanic now!

[@yellowveedub]

Something as easy as a spark arrestor screen being clogged causing that much problem making me look like a fool 🙄. I cleaned my km 56 r and fs 45. Brand new machines 😁

[@TetrisToasty]

Are there any safety considerations to make before pulling apart a whipper-snipper? Like accidentally igniting something via a spark; or not unplugging something that might cause it to start up? It all seems quite straighforward to do, and I'd like to have a go at fixing my troublesome whipper snipper. Great video btw!

[@machinesnmetal]

Absolutely, I would recommend you drain all the fuel from the tank and pump out the carburetor with the bubble to make sure there's no fuel in the system at minimum and then make sure to remove the spark plug before starting work on the machine.

[@philhancock7711]

How about a video of the hand pull rope hard to pull,hangs up when pulling,when I took the plug out it was smooth pulling.someone said to set the valves but I don’t see any to set. Thanks,p.s any ideas?

[@machinesnmetal]

Just remove it and squirt some lubrication (NOT WD40) into the spring behind the white pulley. These models don't have valves to adjust.

[@tradertexas9877]

Mine is still bogging down. I did what you did in the video and tried adjusting the carburetor. It still bogs down and shuts off. Any idea what to try next?

[@machinesnmetal]

fuel filter?

[@TheSandwichMonster]

Have you tried cleaning your carb or putting a kit in? If you're mechanically savvy replace the fuel filter and the diaphragm in the carb and that should fix your issue. I'd bet my bottom dollar it's carb related. I've replaced hundreds of carbs on those due to failing pressure tests. They're not expensive to replace (carb) and often if there's a piece of dirt in the check valve or somewhere even a sonic clean won't bring it around. Might be able to get away with a new diaphragm. Check your local dealer or get the numbers off your carb and bring them to a shop and they can get you a carb kit/carb. Well worth the money as the FS55 is a great rig for the average home owner. 90% of the time it's a plugged exhaust screen we see. But there's a fair few replaced carbs too.

[@kentandconniesmithson1870]

This is a very helpful video. I am having trouble getting the old spark arrestor to fit back in the slot after cleaning. Any suggestions? Thanks. Kent

[@machinesnmetal]

gotta kinda reshape it to fit, or just pick up a new one, they are dirt cheap.

[@kevinpavitt4288]

thanks! very helpful. used the wrong bottle of stihl oil and got 25/1 mix. oops.

[@smallengines1018]

If you don't feel comfortable using a torch to clean the screen, use carburetor cleaner

[@TheHahashishi]

thanks. was hoping for an alternative like this

[@thurm101]

Thanks. I was about to just buy a new part. But I don’t feel comfortable with a torch.

[@steve709061]

You guys are babies. Probably come from California

[@KC-fz6hb]

Thanks man , I never knew that ...

[@morksgrasp1111]

Never stated a fire with my whipper snipper. Can I just remove the spark aspirator entirely and have a working machine? Great vid thanks . P.s new tools ain't what they use to be.

[@bushbasher69]

thanks mate, the internet wins today

[@pt5475]

Thanks from Slidell, Louisiana

[@machinesnmetal]

Welcome!

[@WaveyaAddict]

What if you're in a swamp and the Sparks just go in the water? Can you run this without the screen without damaging anything?

[@machinesnmetal]

You could, but just have to be mindful of the fire risk, as you seem to be.

[@bryannelson7414]

Just had same issue on fs45 but now I can't get an smooth idle it surges up and down while idle but runs great while not idling what would cause that?

[@machinesnmetal]

loose carburetor?

[@delbertsmith5865]

Thanks!!

[@slimsqde7397]

soaked mine in gas and used a air compressor, worked great

[@christianfielden7284]

Can you completely remove the spark arrestee as well? Or will it not run without it in there?

[@machinesnmetal]

You can but then you won't be arresting the spark and that could be a safety issue depending on how dry it is where you live

[@donemmanuel4226]

Great video. I have an identical model hover I cannot locate the spark arrestor. Any ideas?

[@machinesnmetal]

Perhaps someone has already removed it?

[@shannoncole6425]

Perfect! Worked like a charm!

[@bobdegutis302]

Thank you, this video saved me!

[@machinesnmetal]

Glad it helped!

[@breaddrinker]

I have this same model. The FS 55 RC - except on mine, it doesn't end and fire out the back like that, it turns sharply into another metal box marked 'KAT'. There's no way of opening it that I can see. Any idea why? I was wanting to clean it out as you did.

[@machinesnmetal]

Can you make a video?

[@breaddrinker]

@@machinesnmetal I'm not sure it would be much of a video :D I've been told they made a version that used a cat. No wonder it gets so damned hot.

[@glen432003]

I don’t have a torch , but I just put mine in a little cup Of gas , let it sit a min swish it around , wipe it clean ?

[@machinesnmetal]

Ive never tried with gas before, always used a torch.

[@ericdstong]

Exactly the problem! Thank you!

[@All-Is-well489]

how can I remove screen that is inside the enclosed muffler?

[@timsoares3625]

just fixed mine tnx dude

[@Amywilliams648]

Wow u made it look new Does your stihll require a special stihll tool to remove

[@machinesnmetal]

I think it was just a standard half inch deep socket

[@altered5874]

I feel like that is sort of like a def system not required at all but government says it is to regulate bs.

[@hermanfreadrich3015]

Your the best help.😎🇨🇦😎🇨🇦

[@jaywenger4775]

Thanks - works perfect now

[@kurterickson2467]

Thanks. Worked great.

[@machinesnmetal]

Glad it helped

[@Blgtn43]

I have the same type, my spark arrestor is completely gone but still bogs down?

[@machinesnmetal]

Check your exhaust port to be sure it isn't closed up with carbon deposits.

[@Blgtn43]

@@machinesnmetal Thanks

[@61soldiergirl]

I’m staring at those gas cans the whole time. But what happens if you don’t use spark arrester at all?

[@machinesnmetal]

You will not arrest the Sparks

[@Newman81964]

I don't even bother cleaning the screen on mine. I usually just remove the screens on any equipment as soon as I buy it and put the screen in a zip-lock baggy marked with the model and brand of machine it came out of and file the screen away in a small box with all the other screens.

[@machinesnmetal]

Thanks for sharing

[@armstrongcuster9262]

Thank you!!! Brilliant!

[@GT-jp4bo]

Thank you sir

[@machinesnmetal]

👊

[@Edward-fs6wy]

I have a FS55RC model. I don't see the arrestor, just what looks like a port at the bottom.

[@machinesnmetal]

maybe someone already removed it.

[@Edward-fs6wy]

@@machinesnmetal maybe previous owner put different muffler on. I don't see anything, it says "KAT" on the muffler. Thx.

[@BigeSnek]

@@Edward-fs6wyYou have a model with a catalytic converter. What happens is that the piece of catalytic converter inside the muffler clogs up with carbon over time. It causes the machine to run poorly. I had the same thing happen with my trimmer. What I did was I just bought a regular fs55 muffler off of eBay (they are about $15 or $20) so that you will have a cleanable spark arrestor like shown in the video.

[@FlintstoneZzz]

Thanks buddy 💯

[@susanr9057]

What if you don't have access to a torch and air compressor? How else can you clean it?

[@machinesnmetal]

Replace it

[@susanr9057]

@@machinesnmetal thank you!!

[@susanr9057]

@@machinesnmetal Okay, I have tried to find the repair/replacement kit for the spark arrestor and have been unable to find it for the Stihl FS55R model weed trimmer. Is the FS 55 and FS55R interchangeable or is there another brand that can be used in the Stihl?

[@machinesnmetal]

try this link www.amazon.ca/Stihl-Muffler-Screen-4140-140-6900-Genuine/dp/B07N15XFQP/ref=sr_1_1?crid=2RH5LLTQFU8WP&dib=eyJ2IjoiMSJ9.HTNDDW5EUOlcIBmdg_xMkQ.RgEICQF3fWwUdECFW2tcK7EHh78uNIzQVemp5UeyFdM&dib_tag=se&keywords=4140+140+6900&qid=1715913016&sprefix=4140+140+6900%2Caps%2C410&sr=8-1

[@susanr9057]

@@machinesnmetal Thank you again!! I don't know who you are or where you're located, but your video was an excellent video. No BS, just straight to the job at hand and you not only showed me and others how to fix our Stihls, but you replied to my 2 problems! I really appreciate your help and when I get the part, I'll let you know how this 68 year old lady made out. Thanks again.

[@aurelioramirez9484]

Cool vid!!

[@EliteStricker]

How do you stop over oiling? I use TrueFuel 50 to 1

[@machinesnmetal]

Stihl makes a premix, I don't like it, seems to be kind of harsh on the fuel lines/ carburetor disphram

[@NellsGaming]

Perfect!!

[@XavierFournier663]

Big thanks

[@rollinwitbigboi205]

I took mines off and that piece wasn't in there after I screwed it off

[@robertmailhos8159]

That is music to my 👂👂 now do you have a video.on to work blade engagement on LT 1000 Craftsman'.riding mower I have one .when I go to disengage the blade,s they will not stop

[@machinesnmetal]

Does it have an electric PTO clutch or the manual swing style lever to engage?

[@robertmailhos8159]

@@machinesnmetal it has the manual blade.engament the slot is shaped like a upside down J the problem is there is too much slack when I go to engage it

[@fernesal]

Do we really need that creen there or we can simply remove it?

[@machinesnmetal]

It's primary function is to catch sparks coming out of the muffler and setting dry grass on fire. I would leave it in and service it as required

[@fernesal]

@@machinesnmetal That's an excuse they use to fool people. Meanwhile they make tons of money at repair shops and selling new ones to none smart users. First of all try setting grass in fire yourself using one . It's possible but not absolutely easy. Thank God I knew about this screen. Now my blower works properly.

[@machinesnmetal]

Only speaking from what I know I remember back in the day we used to have a similar device in the end of our dirt bike tail pipes so that when you were riding in a dry forest in the summertime you did not shoot out some Sparks and set the forest on fire it's called a spark arrestor I do believe they used to check dirt bikes on the trails to see if people had removed the spark arrestors as it would raise the chances of a forest fire. So in my mind the spark arrestor in a trimmer is there mostly for the same purpose.

[@aratneerg1375]

A great way to wake up!

[@richardb7093]

Worked!!!

[@ronniewortham3260]

Great job!!!!!!!

[@ChiDraconis]

third video showing that it is the spark arrester *(sometimes spark arrestor)*

[@RK-nl1hn]

Hi I tried this even removed the mesh still bogging. It only runs without the exhaust mesh plug removed

[@Klein101]

I have the exact same problem, runs great without exhaust add soon as I put it on it stalls out? Did you figure out what was causing this to happen to ures?

[@brianpape6738]

Any chance either of you figured this out? I can’t get it to Run with the exhaust on

[@breaddrinker]

While I take no responsibility for your choices, a lot of people run these without the screens on. They're just there to prevent the liability to the manufacturer around the obvious fire hazards of dried grasses, combined with shooting sparks and the like. If you're aware of it and understand, it's your option as the owner to go naked.

[@machinesnmetal]

Your exhaust port itself might be closed up with carbon, try taking the muffler completely off and look in the port and see if it's closed up like a cave.

[@michaell31]

excess idling contributes to this issue. two strokes by design should be operated at full throttle 90% of the time.

[@alexgrant11]

what if you dont have compressed air?

[@machinesnmetal]

take it to your local power equipment dealer, or neighbors place.

[@Alex_-oc4bt]

Use a tooth brush with some soap

[@user-uk5eb9wx8c]

What if u can't burn it off

[@machinesnmetal]

Buy a new spark arrestor

[@andrew5550]

Just throw the screen away if you don't need it

[@waylonlegend4603]

I always add more oil

[@js_1995x]

That gas is fine. You can't guess the ratio by color

[@charleywalker2982]

👍

[@jimmcconville624]

what about brake cleaner?

[@machinesnmetal]

Never tried..always use a torch myself.

[@jimmcconville624]

@@machinesnmetal the mechanic in me thinks pressurized brake clean will clean anything