How to: Stihl MS290 Chainsaw Muffler Mod, Carb Tuning & Speed Test

[@StephenMattison66]

Great info, Thanks! Especially the part about tuning, especially the demonstration how to set high-limit so it isn't running lean! Perfect demo based on "burbling" sound of engine!

[@oldman1026]

Great, and thank you. No music, no music konsert. Thanks !

[@mpeters5549]

Man i did this mod and swapped out my 20" bar to an 18" WHAT A DIFFERENCE! Like a whole new saw that cuts WAY FASTER! LOVE IT!

[@justinheard5954]

Then again mine is a super ATV

[@allanwells4886]

Nice saw! I did the muffler modifation trick many years ago on my old Stihl 031av. It's still going strong but the anti-vibration rubbers(no springs back then) are well and truly "shot". Mind you it's only 36 years old.(purchased Feb. 1980)

[@nothanks3462]

My completely stock German made UK purchased 2004 ms290 has bigger lower holes and 2 extra holes above the baffle, again its the original standard exhaust. Looking inside the baffle is very basic and pretty open, I was only checking the engine so left it alone, but if yours is like the video example then it definitely won't hurt to open it up a little and adjust the carb accordingly.

[@King7765]

I've always interesting how companies make products in different countries. We have to deal with EPA regulations over here.

[@MrZimmaframe]

The normal oem carb setting I think is about 1 turn for the L and H, do you add an extra turn making it 2 turns total for L and H after the modification? Or just one turn? Cheers, good easy mod to do 😃.

[@giovannirevilla2638]

It’s alive!!! Very nice!!!!

[@ndc2520]

A muffler mod (within reason, and along with a carb retune) will not be the demise of a non-pro MS series saw. Lots of MS290 & other non-pro MS series saws fail early due to those plastic bearings they use in them now, however. If you don't catch it in time (most don't, unless they get lucky & notice the plastic debris while replacing something else), it'll destroy the entire engine. That's why these new non-pro saws will never last like the old ones did. The conscientious, planned self-destruction of their non-pro saws in a few short years of use is obvious in these new homeowner oriented saws, since quality bearings wouldn't have cost much more to install, and would have provided much longer service life..

[@Oakclimbercj]

cool where did you find out they have plastic bearings, and wear are they in the saw?

[@Wanous-hv7zo]

Chris Foxworth all the new non pro saws use china bearings in them. they fail all the time

[@RS-uo2nd]

N DC The issue with the non pro saws from Stihl are power to weight, not some plastic bearing made up bullshit

[@rivtool515]

No plastic bearings in any stihl saws. That being said the needle bearing that the clutch and sprocket rides on has a nylon carriage. These bearings are subject to lots of nasty stuff and wear out more frequently then other bearings on the tools. Stihl makes these with nylon carriages so when they do fail, and they will at some point, the bearing carriage does not destroy the crank shaft. Cost wise just about any sthil saw that needs a bottom end will probably cost more including labor then a new saw so the nylon carriages are a welcome change. Just ask anyone with a Husky that has a well worn clutch bearing and has had to buy a new saw:)

[@joshhead6133]

I build high quality chainsaws out of play dough and every time I blow a rod I just crumple it into a ball and re build it from scratch. You guys should try it. I can cut through a two meter thick maple tree in 2.1 seconds. Ya the saw runs at about 76000 rpm. Boss as fuck right. Plastic bearings and all

[@robertpagans2973]

I love those sthil chain saw.

[@joe54chn]

With the increased flow through the exhaust, however much you adjust the stock carb, you are limited. But if you swap the carb for that from a MS460 its a different story altogether! It is a straight fit.I have done it.

[@Cody73]

joe54chn It's nice to know that the 460 and the 290 carbs are interchangeable! However, I don't think the stock 290 limits the saw with a muddler mod, the same carb is also used on the stock 390.

[@joe54chn]

Cody73 Agreed that onlyy diff between 290 and 390 carbs is the 0.56 and 0.58 fixed jets. But the wider venturi in the 460 carb allows better intake of air. You can experiment with a wide range of jets (390, 460, 660 jets) to suit you.

[@Cody73]

joe54chn Thanks. That's great information!

[@Rick_Sanchez_C137_]

Cody73 Hey man, great vid! I am likin what Joe is saying and just bought a used 390, have you done a vid on the carb upgrade with a mod? I’d love to watch it and know the results! PS. I get it, it’s hot where you’re at and you’re still young enough to think nothing bad will ever happen to you.... nobody gets out alive, safety equipment is for prolonging the inevitable, wear it....and long pants when working around spinning blades and bar chains... Thanks!

[@daveberntson4081]

Good video! Thanks for demonstrating the sound of a "burble" at full throttle. Did the muffler mod require the carb tuning? Thumbs up.

[@Cody73]

Glad it helped! Yes, porting the muffler increases airflow, which would cause it to run lean if you don't retune the carb.

[@TommySmokes262]

Did you use standard full chisel for the stock cutting, then switch to Rip Skip FC for the mod'd saw? If you did, that would account for most of the time reduction.

[@Cody73]

+Tom f Only partly. I tested it with the RS chain before the muffler mod, and although a significant improvement over stock, it was no where near as fast as after the muffler mod.

[@walterkersting1362]

Great for when the neighbors start their oom pa pa music.

[@deanmclaughlin1305]

Just curious how the saw lasted and performed...I'm watching 5 yrs later

[@Cody73]

Don't use it a ton but it's still going strong.

[@6900pilot]

Hi ya, I was going to do this mod, I opened up the muffler today and when I looked inside there was no spark screen and to my surprise there were two more elongated holes above at the top of the muffler, where you finished up in the illustration which is very good by the way. The saw is an 029 super. Plenty of power, never opened before had saw from new.. I decided to leave it as is. Do you have different laws in the us? Were in Ireland saw is mid nineties. Cheers!!

[@Cody73]

Thanks for the kind words! Yes, the EPA is very stringent with small engines here in the US. Also your saw is older. I think the US 029s had a better muffler as well. Cheers!

[@crocellian2972]

Is there on OEM muffler cover for AU like there is for the MS660? Saves a lot of time and acts as a redirector for the exhaust.

[@packrat76]

Does that saw actually stay running at idle or does it conk out within 30 seconds? I've been told by a small engine mechanic that you don't want to reduce the back pressure too much or it won't idle for long without stalling.

[@Cody73]

packrat76 It idles fine. All you have to do is adjust the Idle and Low mixture screws on the carb.

[@packrat76]

With all the adjustments is it actually in the rpm range of an idle?

[@Cody73]

packrat76 Although I haven't tested it with a tach, the rpm is definitely at idle.

[@packrat76]

OK. That's surprising. I opened up the muffler a little on my old Poulan, but didn't want to drill out a bunch of material in the muffler. Does it seem to noticeably run hotter or cooler? I've heard both sides of the argument. Depends who you ask.

[@Cody73]

packrat76 If you just open up the muffler (without richening the fuel mixture), it could run hotter. Opening the muffler increases airflow, and thereby leans the fuel mixture. Because it is a 2-stroke, the fuel itself acts as a lubricant and coolant, so when the mixture is leaner, there is less lubrication and thus more heat. But, if you do adjust the carb in addition to opening the muffler, that will lower engine temps because of the reduced backpressure.

[@scavuman]

Excellent Video , Very Well Done, Thanks : )

[@buckeyejake9014]

It looks like something happened while you were tuning the carb, just before you gave the thumbs up, around the 7:15-7:20 mark. After that, there is oil dribbling down the side of the saw...

[@Cody73]

+Jake Watts That's just oil that's flying off the chain. Nothing coming from the engine.

[@realgagne2956]

I wish you could have a look at the muffler on a Dolmar PS540....which is 54 cc. A very good saw compare to Stihl. The muffler doesn't have any holes other than the main exhaust hole. I don't want to drill at the wrong place and wreck it. Could you have a look at One online and tell me if it can be done?

[@Cody73]

I took a look at some Dolmar PS540 mufflers on the internet. It looks like there shouldn't be a problem.The best advice I can give you is to take off the muffler, and drill a few holes directly opposite to the exhaust port, so it's just a straight shot out. Let my know how it goes!

[@desikronenberg7218]

Three questions. 1) What size drill bit did you use? 2) Do you drill through the entire muffler, or just the face plate show in picture? 3) Do you still put the spark screen back on after drilling? Thank you.

[@rivtool515]

The spark arrest screen is required in the EU, US and CA in all places and its illegal to remove it. Thousands of $ if you get caught.

[@robotman18]

RIV` TOOL only illegal if you are working in a forest or as a contractor

[@rhysholley8289]

How do you stop or get the metal shavings out or stop them getting into the engine. Regards

[@brewsterly2927]

You take the exhaust off and do the job properly, like many videos show, not like this botch up.

[@jaw3895]

Being cheap, as myself, I did not want to look for a “muffler shop” that know nothing about saws (most only prefer stolen catylitic converter work) and a small engine shop won’t take the liability… soooo I kept a shop vac with a small attachment going while I do Muffler Mods.

[@billwilliams9897]

Okay man, I have this exact saw, the other day I went to start it and kept flooding. Ive had 3 stihl saws and know how to start them, but it would start for a second then die. I always use 100% gas with stihl oil. But I noticed my muffler was a little loose, after examining it one of the bolts had torn loose of the muffler on the outermost side. So there were only 2 nuts actually holding it on. Could this cause my saw not to start right? I'm looking online for mufflers right now. Is there a muffler you would suggest? Or could you send me a link so I can order a decent one? Thank you very much Sir, awesome video.

[@Cody73]

+Smokin Bill Williams I can't say for certain, but I doubt the muffler is causing it to fail to start (you could technically run it without a muffler, although that is not advisable). Are you sure the carb is in good condition and the mixture screws are adjusted correctly? Try advancing both the idle and low mixture screws. Let me know if that works or you find another solution!

[@billwilliams9897]

But I definitely need one. This should fit shouldn't it? www.amazon.com/gp/product/B00SH4UPVA/ref=ox_sc_act_title_1?ie=UTF8&psc=1&smid=A1KUO52RTCWJNS

[@Cody73]

+Smokin Bill Williams Yes! That looks like it should work.

[@billwilliams9897]

Ill try what you said. Ive never had problems with starting my stihl saws or weed eaters, and never run any ethanol, and my other saws are starting right up. So its definitely a problem with this particular saw.

[@Cody73]

+Smokin Bill Williams I understand. Over time, the carb might need a little adjustment to keep the saw working well. I hope that works!

[@toonsesthecat3950]

Great vid .... now go get some stihl saw pants and a helmet with muffs/shield ..... if you spend any time behind that saw they are a great investment

[@Cody73]

Thanks! I have been giving some serious thought to the chaps and helmet now that I'm using the saw more... I'm glad the video was helpful!

[@347firedude]

toonses thecat I am going to second that. just getting started with pro tree work. safety is a must from the items you mentioned in addition to gloves and some basic first aid training. something no one mentions until "it" happens. saws don't care what they bite into. now do not go safety over bored. just a few checks and youre good to go. great video as well. I will try this on my saw. I let it run dry on gas a couple of times and killed the engine. rebuild....a 390 engine in a 310 frame....what a beast

[@jaw3895]

GOOOD Chaps and steeltoe boots are a requirement. Look up how chaps work and the people regret not having them. You don’t need to be a logger to protect your limbs

[@jaw3895]

$100 more than likely 1time buy? Or your limb/life/hospital bills/no work… Even cutting branches in your yard DEMANDS protective equipment.

[@jimmyb207]

I'm shocked at the number of videos showing guys using a chainsaw without wearing a pair of chaps. My legs, and maybe even my life has been saved a few times by my Kevlar chaps. Stops the saw instantly when the chain makes contact. My biggest mistake has been pushing myself too hard. I get careless when I get tired. Anyway, my 029 Super has been running great for over 20 years no mod. But, considering it. I cut down about 3 - 4 cords of fire wood a year.

[@ryanwightable]

Great video! I've also got the 290 and was thinking by performing your mod I could increase the bar beyond 20". Have you tried it?

[@Cody73]

+Ryan Wight No I haven't. But I've heard of others running 25" bars effectively.

[@Cody73]

+Ryan Wight No I haven't. But I've heard of others running 25" bars effectively.

[@rivtool515]

Do not do this to a 290. Its not a full industrial saw. It wont last. Buy the saw you need. A 311 with a 25 inch bar and chain is 20$ more then the 291 and takes the 25 inch bar like a champ!

[@KimballCody]

I have a MS210 and I don't think the carb adjustment screws have limiters on them. Do I just need to open the muffler and tune it from there? Right now it will start but the first few throttle ups it studders and boggs down. I was reading that the muffler screen might be plugged. Any thoughts?

[@Cody73]

AzDadOnFire I'd suggest that you first try to get it running well and then do the muffler mod - just so you aren't dealing with two different issues are the same time... If you think the muffler screen might be clogged, you can just remove it and try running it without. If it still stalls, try adjusting the H screw on the carb. If the high mixture it way too lean or rich, it can cause the saw to stall when revved. Also, the limiters are just those red plastic caps that fit over the actual adjustment screws and restrict the amount you can adjust them. If you don't have the limiters, then just open up the muffler and tune!

[@KimballCody]

Ok, thanks

[@Wanous-hv7zo]

KimballCody muffler is all different on a ms 210. you cant do the same thing this idiot did

[@rivtool515]

You have no business giving people advice on Stihl saws..... Are you even gold certified yet?

[@pyr0674]

You did the high adjustment screw but what about the low adjustment

[@King7765]

These mods really only affect high rpm fueling.

[@pyr0674]

@@King7765 got ya

[@redneckeliot032]

Hey did you put more oil in the gas because people say it will run hotter with the muffler mod?

[@Cody73]

No I didn't. Actually the opposite is true. Because a muffler mod reduces gas pressure, and allows the hot exhaust gases to exit the engine quicker, the saw will run cooler after the muffler mod.

[@redneckeliot032]

OK thanks. The saw I am modifying is my echo cs 400 chainsaw. I know it will avoid the warranty.

[@redneckeliot032]

By the way I just subscribed to your channel.

[@Cody73]

Thanks for the sub! Much appreciated. Your saw will run better and last longer with the muffler mod (because of the lower engine temps).

[@redneckeliot032]

OK thanks.

[@Anonymous-uu5nc]

Would you add a 25 inch bar after the muffler mod?

[@Cody73]

I personally haven't tried that. However, I've read of people who put a 25" bar on their muffler-modded 290 and it worked fine. That said, the 290 would probably work best with an 18-20" bar. So I'd suggest, if you need the 25", go for it; but if you don't, then stick with an 18-20".

[@Wanous-hv7zo]

Tim B a ms 290 does not have enough cc to run a 25 inch bar very good.ms 290s come with 325 pitch chain so you would have to switch it to 3/8 pitch and the ms 290 is way under powered to run a 25 inch bar with 3/8 chain on it. this guy dosnt know shit. his muffler mod is a joke

[@Wanous-hv7zo]

Tim B a ms 290 does not have enough cc to run a 25 inch bar very good.ms 290s come with 325 pitch chain so you would have to switch it to 3/8 pitch and the ms 290 is way under powered to run a 25 inch bar with 3/8 chain on it. this guy dosnt know shit. his muffler mod is a joke

[@oby-1607]

This probably works. I ran open headers in my car for a while and it ran pretty good but after a while it was just too loud. Mind you, the duel Holleys on top of the tunnel ram and racing cam didn't help either.

[@yamahondazuki95]

why do you want the saw to run a bit rougher rather than smooth in the high rpm?

[@Cody73]

Because in a two-stroke, the fuel acts as a coolant for the engine, it it important to make sure it doesn't run too lean. If a two stroke runs too lean, it will overheat, and maybe even seize-up. Tuning it to make that slightly rougher noise at WOT ensures that it's not running too lean.

[@burtvhulberthyhbn7583]

He's absolutely correct. richening the mixture until a slight burble or "4 stroking" means the mixture is just right under a load. every saw is epa' leaned for emissions but this costs power and most importantly shortens the life of the engine. I didn't mod my muffler but I cut off the limits on my 455 husqvarna and it runs astoundingly better.

[@burtvhulberthyhbn7583]

the limits are plastic limits around the hi and lo adjustment carb screws. you can saw these off so you can rotate the screws more than the limiters allowed. usually approx 1/2 turn counter clockwise works much better than EPA leaned.

[@Wanous-hv7zo]

wildwilllis1 govener? Stihl ms 290 dosnt have a govener you idiot. so many stupid people on youtube including this idiots chanel

[@Wanous-hv7zo]

Burt Hulbert how are you going to saw them off when they are down inside there on the carb? you are a dumb ass idiot. take the carb off the saw take a small flat screwdiver and pry the red plastic limiters off and the aluminum part around the limiters

[@weldweld5629]

Got one for a ms 250?

[@atlas3863]

get an Expansion chamber for a two stroke RC car like the HPI or king motor Guaranteed that Puppy will be throwing mulch. and sound like a dirt bike doing it. they use the same basic engines might need to make an adapter plate to go from your 3 bolt Square port to a 2 bolt round.

[@Rick_Sanchez_C137_]

speed demon Ummm, can you do a video on that? Seriously!

[@riflebear1711]

Post a link to one please!

[@yomommajumprcables]

Damn she sounds good!!!!!

[@tinman1955]

I've read that running these things on 32:1 fuel rather than 50:1 makes them last forever. Any thoughts on that?

[@militarychevy711]

+Tin Man The problem with running Extra oil is that is clogs up the small passage ways in the carb and can cause the diaphragms to stick. Also will cause the fire screen to fill with carbon. Not running Enough oil will cause the saw to burn up. I've seen several 20 year old saws that have been Taken Care Of from the time they were new running perfectly on 50:1. Long as the A/F is kept clean...your fuel tank is clean and the fuel fresh...and the carb adjusted to factory specs...as well as usual light servicing they will last a Long time. Even a sharp chain will make your saw last longer. The better you take care of it the longer they last. At the shop I work at the Most common problem with 2 stroke equipment is fuel related.

[@craigtimmons3468]

On new and stock saws I run 40:1 mix with 1oz MARVEL MYSTERY OIL added to every 2 gal mix, I have had unbelievable results with this mix on my stock saws, still going strong after more than 20 years with nothing more than a spark plug, fuel line and air filter changes. On my NON stock saws I run a 32:1 mix with 1oz marvel mystery oil added to every 2 gal mix due to the extra stresses that you are putting on the engine, I've been running my 2004 Husqvarna 575xp over 10 years on the stock crank bearings with port/ timing moods, Squish increased by cutting base and using thinner hand made base gasket .010 that resulted a total squish of .018, gasket matched the transfer ports and muffler and also preformed a muffler mod. and ignition timing advanced. I have to ask everyone that disagrees with this, would you run your car with just 1 qt of oil or 4 qts? I believe 99% will answer 4 qts. Yes I may have to change a couple extra spark plugs but what's a couple dollars compared to an $900 new saw. I started running an e3 spark plug 2 years ago and have not had to change it since. I run nothing but Lucas semi synthetic 2 cycle oil mixed in at least 92 octane low ethonal gas. For long storage I mix sta-bil for ethanol gas in a small amount of fuel mix and run it thur my saws for at least 10 mins before putting them up. Yes my saws smoke a little bit but remember we are dealing with a 2 cycle engine here the F"N EPA dictates no smoke here not the MFG.

[@2sheetstothewind484]

Not too happy with my stihl`s chain oilers. They require too much maintenance making them doubtful for performing. Have an old Poulan that`s never needed the attention these stills require.

[@davidbrown4449]

Craig, I'm a little unclear on your 40:1 mix. Do you run 2 oz of Lucas 2 cycle oil, plus one oz of marvel mystery oil in every two gallons?

[@jaw3895]

Just keep” Poul”ing on man…

[@TheVaevictus24601]

So that chainsaw take it's self for a walk? Nice Vid!

[@joematus410]

Good

[@dimitriosmag5760]

is it now more noisy? (with extra holes) or not?

[@Cody73]

Yes. Definitely. It is way more noisy now. It is extremely loud.

[@rocksr.4738]

Dimitrios Mang

[@Wanous-hv7zo]

Dimitrios Mang you dont drill holes in the center like this stupid ass did

[@andrerossi5010]

It would be possible to increase the air intake of the chainsaw so that it gains power?

[@Cody73]

Andre, yes I've heard some people replace the carb with one from a larger saw.

[@robertpagans2973]

Frist thing i would do take that dam sceen out of muffer.

[@Cody73]

Robert Pagans Yep. I remove the screen too. However, the only way to get big power gains is by doing a muffler mod and re-tuning the carburetor.

[@kipmyers3435]

To the sthil dealer ...i bought a new sthil and in 5 tanks the quote auto chain oiler went out destroyed the clutch broke the chain brake which broke the case ...this saw was 2 months old had only sthil oil and fuel and i gotta wonder would a clone hv been any worse? But say i had a muffler mod which i did not then that would be ur excuse to not cover the saw when in fact an expansion chamber on a 2 stroke really helps...i raced 2 stroke go karts for yrs i know what last and what dont and it does help the man is right you are wrong glad ur not my sthil dealer ...who knows maybe you are is why they want to play games about replacing my saw...ive ran many 2strokes on alky and they run cooler so why does sthil not do that too? Bc the goverment wont let them...its easy to see why ur a dealer not a saw tech...this guy told you right u sthil dealer are why people do buy china saws

[@karlmadsen3179]

huh?

[@robertpagans2973]

They need to see how i work with those sthil s .

[@braydengrimaldi6644]

Drilling holes in a muffler doesn't automatically give you power. To large an opening will decrease back pressure and you lose your exhaust timing. And subsequently power. If you were going to mod a saw and knew what you were doing you wouldn't waste your time on a 390 I give your top end 5 hours maybe.... also nice use of PPE...

[@Cody73]

Indeed, if I had just drilled holes in the muffler, the saw wouldn't even run! That's why the carb has to be re-tuned. However, a muffler mod has no negative effect on reliability, in fact it will make the saw last longer because it runs cooler. Also, 2 stroke engines work optimally with an exhaust port that is 80-100% of the size of the cylinder port. If you noticed I left on the front plate on the muffler, that will provide more that adequate back pressure...

[@braydengrimaldi6644]

Lol true. And I was referring to the timing of the pressure wave, not just the amount of pressure

[@theone8308]

I suppose those Germans don't know how to build them right theyve only been doing it since 1926, let me know how long this saw last. Don't you think if it were better to have more holes in the muffler stihl wouldn't have already done it ? DONT do this.!!!!! Sure you can make a saw louder and a little faster but the lifespan will suffer. I have seen these nuts in my stihl dealership over the past 14 years wanting me to (fix) there saws under warranty and I tell them they are s.o.l.

[@Cody73]

You must have not have used a saw much during your 14 years at a dealership. Yes, there is a reason for the number of holes that Stihl puts in their mufflers - government noise and emission regulations. Stihl did not design those mufflers for the best performance or longevity of the saw, but to satisfy those pesky government regs. It's quite easy to understand that by opening up the muffler, you allow the heat to escape the saw quicker - and the only side-effect is that your saw runs cooler, and hence will last longer. Many an experienced saw user will confirm this. Next time, please try to educate yourself on the issue you are commenting on, or at the very least, take a dose of civility before you mash your keyboard.

[@rivtool515]

We have a local shop here in NJ that does these silly mods. I get to rebuild them all so its more work for me.. All this does is increase the top end heat, lean out the saw at high rpm and make lots of noise drastically lowering the service life of the tool. The stock carbs need to be modded in order to get the mix correct and in most cases a port and polish is also called for. These mods are a complete waste of time and $$$$$.

[@Cody73]

RIV` TOOL if you watch the video, you will see that I do adjust the carb. It's not running lean. I really don't understand why someone would hate a free mod that drastically improves the performance of your saw. And if you doubt that it makes it faster, you've definitely never tried one.

[@walterkersting1362]

Dealers like you are why I buy Chinese off of the internet. You did it to yourself.

[@carryontrekkin1765]

A good muffler mod is great. This is a really bad job though, you should be measuring your exhaust port before doing anything and adjusting muffler output accordingly...google it. Just drilling loads of holes willynilly is retarded.