# Echo Cs 400 Mods



## Nicutmafia (Jan 24, 2015)

Hey guys I'm new to this site but what better site to get chainsaw wisdom than arboristsite? Hello from Oklahoma. 
I just acquired an almost new CS 400 today for $150. This thing looks like it may have been used to cut a few limbs. It's my 1st Echo as I usually buy Stihl saws. I have 2 questions about the Echo. I hear that they are set really lean from the factory and that the mufflers really choke the saw down. I know that there are mods that you can do for the muffler and remove the limiter caps and retune. Can someone please fill a new guy in on these modifications and maybe someone has written something up with pictures on the muffler mod. Thanks and all information will be greatly appreciated.....


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## RedFir Down (Jan 24, 2015)

Congrats on your cs-400 score!
Yes they normally do come lean from the factory.
Here is how I muffler mod them.
I found using a 7/8" whole saw bit get rid of the CAT in a hurry. 




Next open up the outlet...




Then open up the deflector...




Do all the grinding with the muffler removed from the saw and make sure to get ALL the filings out before putting the muffler back on (I wash mine out with hot soapy water)

As for the carb limiters... If your not familiar with removing them I suggest you take the carb off first. Then you will see the red caps have 2 tabs. Line them up with the cut outs on the carb body, thread a sheet rock screw a turn or so into the limiter and pull out with some pliers. Trim the tabs off the limiters and push them back on. 

This should give you a good start. 
Are you familiar with tuning a saw?


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## Rokon (Jan 25, 2015)

The best mod for a cs-400 is to keep the chain sharp. IMO that's one of Echo's best late model home owner saws.

A clean, used cs-400 STOCK on Craigslist worth 100-150. Modded cs-400, less than 100.


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## jrs_diesel (Jan 25, 2015)

I bought one last fall and am impressed how well it cuts in stock form. Mine came with Oregon 91PX on it, and from what I read here, a muffler mod and Oregon 91VXL (non-safety chain) really makes the CS-400 come alive. I have not modded mine yet beyond adjusting the carb more rich than factory settings (want to keep the warranty).


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## Chris-PA (Jan 25, 2015)

jrs_diesel said:


> I bought one last fall and am impressed how well it cuts in stock form. Mine came with Oregon 91PX on it, and from what I read here, a muffler mod and Oregon 91VXL (non-safety chain) really makes the CS-400 come alive. I have not modded mine yet beyond adjusting the carb more rich than factory settings (want to keep the warranty).


I have a lot of lo pro chain, and I'd put my money on the 91PX for speed. Those ramped drive links don't get in the way at all, and the chamfer chisel cutters on the 91PX are fast if properly sharpened. The biggest problem is the cutters are short so it's a poor value.


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## Nicutmafia (Jan 25, 2015)

Will they remove the limiter caps and tune at the dealer? I have an Echo dealer within 10 miles? Is there a muffler swap that can be done to accomplish the same thing as the muffler mod? Thanks for all the great information by the way.


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## RedFir Down (Jan 25, 2015)

Nicutmafia said:


> Will they remove the limiter caps and tune at the dealer? I have an Echo dealer within 10 miles? Is there a muffler swap that can be done to accomplish the same thing as the muffler mod? Thanks for all the great information by the way.


No dealers will not remove the limiters caps entirely (they are not "allowed" to... EPA reasons). Im sure they will tune your saw for you though. But if you take it to them after you opened the muffler up im not sure how that will go over... they might turn you away. Most all dealers will only work on 100% stock saws. (I was recently told by one of my dealers that I was going to blow up one of my Autotune saws by opening up the muffler.)

No there is not a non cat cs-400 muffler available.


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## Nicutmafia (Jan 25, 2015)

RedFir Down said:


> Congrats on your cs-400 score!
> Yes they normally do come lean from the factory.
> Here is how I muffler mod them.
> I found using a 7/8" whole saw bit get rid of the CAT in a hurry.
> ...



RedFir Down, is that the part of the cat that you took out in the 1st photo of your post?


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## RedFir Down (Jan 25, 2015)

Nicutmafia said:


> RedFir Down, is that the part of the cat that you took out in the 1st photo of your post?


Yes that is whats left of the CAT after my 7/8" bit got done with it.

You can drill, pry and pull the cat out if you dont have a 7/8" bit but it is very time consuming and a PITA to say the least.


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## mountainlake (Jan 25, 2015)

RedFir Down said:


> Yes that is whats left of the CAT after my 7/8" bit got done with it.
> 
> You can drill, pry and pull the cat out if you dont have a 7/8" bit but it is very time consuming and a PITA to say the least.




I use a 1 " drill bit. Steve


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## RedFir Down (Jan 25, 2015)

mountainlake said:


> I use a 1 " drill bit. Steve


If I remember right a 1" hole saw bit was a tad to big.

Where you using a traditional metal drill bit?


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## BusyBeaver (Jan 25, 2015)

RedFir said he used a 7/8 hole saw. That's what I used too. Works perfectly.
BB


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## mountainlake (Jan 25, 2015)

A 1`" fits good but looks like a 7/8 does the job just fine. Steve


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## Nicutmafia (Jan 25, 2015)

Ok I'm pretty clear on the muffler mod with the exception of opening up the deflector. Any special instructions here?

As for the limiter caps, I have located these and just need to thread a drywall screw into them and they just pull out? Then there are some tabs I have to trim off them? I attached pics of the caps so maybe you can help me understand a little better. I also attached a pic of the saw. Thanks....


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## M&Rtree (Jan 25, 2015)

I did the same to mine. My cousin talked me right out of the saw. He ported it and said he got greedy after awhile and end up over revving it. I had it 2 or 3 years was a great saw. Especially for the 80 bucks I paid for it. Power is similar to my 543xp.


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## BusyBeaver (Jan 25, 2015)

Here's what I did:
BB


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## Nicutmafia (Jan 25, 2015)

If I do these mods to my saw, will it in any way adversely effect the saw, like cause it to over Rev and blow up or anything like that? Would removing the limiter caps and re-tuning without middling the muffler accomplish anything? What I am trying to achieve is getting this saw to run correctly without having to worry about premature failure due to it running too lean. I wouldn't mind a bit of performance boost but that's really not necessary as I will only be using it to cut approximately 30 ricks of personal fire wood per year and also the occasional clean up. Thanks...


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## Philbert (Jan 25, 2015)

Here's a related thread, FYI. Unfortunately, many of the photos have been lost.

http://www.arboristsite.com/community/threads/echo-cs-400-chainsaw-muffler-mods.129928/

Philbert


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## jughead500 (Jan 25, 2015)

I done a muffler mod on my buddys cs400 today i ground out the rear deflector behind the cat with a dremel and just drilled out the cat with a 7/8" drill bit.and only took out 1 of the sections on the front outlet.it really did bring it to life.even the small port before the cat would choke it out.i don't know how it breath through both it and the converter too.i still have to fine tune tomorrow.


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## stubnail67 (Jan 25, 2015)

jughead500 said:


> I done a muffler mod on my buddys cs400 today i ground out the rear deflector behind the cat with a dremel and just drilled out the cat with a 7/8" drill bit.and only took out 1 of the sections on the front outlet.it really did bring it to life.even the small port before the cat would choke it out.i don't know how it breath through both it and the converter too.i still have to fine tune tomorrow.




pics of before and after??


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## jughead500 (Jan 25, 2015)

Would have like too but just wasn’t in the mood for pictures today.blocked up 5 big sugar maples before i done this.my back is pretty well screwed right now.just done the sugar maples to tune a few saws and get a feel for a couple of saws i have been working on and help hold onto sanity.
If i were to have been able to post pictures they would look pretty much like redfir's about the only thing i done different than red was use a regular 7/8" drill bit in my dewalt in a vise.


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## rmotoman (Jan 25, 2015)

Nicutmafia said:


> If I do these mods to my saw, will it in any way adversely effect the saw, like cause it to over Rev and blow up or anything like that? Would removing the limiter caps and re-tuning without middling the muffler accomplish anything? What I am trying to achieve is getting this saw to run correctly without having to worry about premature failure due to it running too lean. I wouldn't mind a bit of performance boost but that's really not necessary as I will only be using it to cut approximately 30 ricks of personal fire wood per year and also the occasional clean up. Thanks...


You don't have to do the muffler mod but it runs so much better when you do. I first adjusted the carb because mine was so lean from the factory. Later did the mm. It's worth the effort. Cuts way faster.


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## stubnail67 (Jan 25, 2015)

im still breaking mine in it runs pretty good as is.... trying to break it in before i tear it apart guess if its adjusted right does not matter .....its adjusted a lil rich right now 3 or 4 tanks so far


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## Nicutmafia (Jan 25, 2015)

rmotoman said:


> You don't have to do the muffler mod but it runs so much better when you do. I first adjusted the carb because mine was so lean from the factory. Later did the mm. It's worth the effort. Cuts way faster.



Is there any adverse effects to doing the muffler mod? I'm definitely going to pull the limiter caps and re-tune. I'm still kind of on the fence with the muffler mod. Do you have to re-tune after modding the muffler if you have already richened the mixture up from factory settings?


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## jrs_diesel (Jan 25, 2015)

I believe you do. If I've read here correctly, the engine will run lean after a muffler mod since it breathes better.

I also saw a post further up asking about over revving these saws. I suppose it's possible under the right (or wrong) circumstance, but the ignition has a built in rev limiter that tops out at around 12,500 RPM.


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## RedFir Down (Jan 25, 2015)

Nicutmafia said:


> Is there any adverse effects to doing the muffler mod? I'm definitely going to pull the limiter caps and re-tune. I'm still kind of on the fence with the muffler mod. Do you have to re-tune after modding the muffler if you have already richened the mixture up from factory settings?


As long as the saw is tuned correctly after you muffler mod it that NO, there are no ill affects to opening up the muffler.
The saw will run cooler which promotes longevity and it will also have noticeably more power... it will probably hold 500+ more RPM in the cut.

I really dont know how to answer your second question here... to many variables to say yes or no.
I suggest you send some time on youtube on how to tune a chainsaw. There has been alot of site members post videos on this subject.


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## stubnail67 (Feb 12, 2015)

so here are my orange echos.... when did they go to plastic handles?i had them both out and just noticed it... also i noticed my one i just bought cs 400 plastic handle has a different chain if you look in the pics of the 2 bars you may be able to see.... is this the P-pro series chain from echo?


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## stubnail67 (Feb 12, 2015)

group


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## Full Chisel (Feb 12, 2015)

This video will help you get your saw tuned. Keep in mind your Echo has a limited coil so it will sound like it's 4 stroking when it hits the limiter. Richen the H to where it doesn't drop much RPMs off full throttle when the limiter kicks in...there is a slight delay after it spools up, you can hear the difference. It's best to tune in wood, richen it up to where it burbles heavy in the cut and lean it out slowly to where it cleans up but still burbles when you let up on it. But definitely get those tabs off and richen it up some.


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## stubnail67 (Feb 12, 2015)

the limiters are all off and the 2 new ones are pig rich till i do my next job and get some 10 to 12 inch wood.....


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## stubnail67 (Feb 12, 2015)

yea i don't like the limited coils at all i like the poulan saws like he showed... i just sold many of my old saws... time to go all new.....equipment...


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## creami (Feb 20, 2015)

I found a VERY cool guy locally who helped me out with a muffler mod last night with my CS-400. I figured I would throw up a few pics of it. He gutted the cat, opened the exit hole a bit and widened the deflector. Then he pulled the limiter caps with a (magic tool) and retuned it. 
We tested it right after on a nice piece of mesquite. I can truely say this is an altered beast! In hind sight, I believe I could have done the muffler mod myself but where I was chickening out was pulling the limiter caps off and retuning. I wish I had a "magic tool"! I finished by painting it with VHT Flame Proof Flat Gray Primer.

Big thanks to you man


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## jughead500 (Feb 20, 2015)

Looks Good.Glad you got Her Modded.Your Definately Going to like it.


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## creami (Feb 20, 2015)

Thanks Jughead, I'm loving it for sure!


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## stubnail67 (Feb 20, 2015)

ya think it will not melt anything with no deflector? looks mean


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## creami (Feb 20, 2015)

I still have the original deflector that I might cut just half way like others have done.


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## stubnail67 (Feb 20, 2015)

creami said:


> I still have the original deflector that I might cut just half way like others have done.




look forward to some updates.... i like the way it looks bet it sounds mean


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## creami (Feb 21, 2015)

Ive only cut a little bit with it before the mod, but enough to give a comparison. I will put it like this, before it was a very good cutting saw. Now it is a black mamba that screams baaa and rips through wood with a vengeance. It was quite shocking to me just how much more power was gained from this. Hopefully, it will make the motor last longer as well. 
Good folks here.


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## mountainlake (Feb 21, 2015)

The first time I muff modded a CS370 cut times went from 15 seconds to 9 seconds. The CS400 saws have quite a bit more power than the CS370. Steve


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## NewShockerGuy (Sep 19, 2015)

Are the two holes drilled into the deflector plate needed? Also is there a pro or con to completely eliminating the front of it like see above by creami vs OP?

Thanks,
-Nigel


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## bikemike (Sep 19, 2015)

Nicutmafia said:


> Ok I'm pretty clear on the muffler mod with the exception of opening up the deflector. Any special instructions here?
> 
> As for the limiter caps, I have located these and just need to thread a drywall screw into them and they just pull out? Then there are some tabs I have to trim off them? I attached pics of the caps so maybe you can help me understand a little better. I also attached a pic of the saw. Thanks....


Just thead in the drywall screw till it stops then turn the limiter to the left till it stops and pull the cap out. No need to trim them just leave em out


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## Full Chisel (Sep 19, 2015)

^that's what I did to mine and no issues holding a tune at all. One of the tabs fell into the case and couldn't be found. It got eaten by the flywheel, so I didn't bother putting the other one back on.


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## bikemike (Sep 19, 2015)

You have to remember tune after any mod or weather change no caps makes it easy. Tune it in the cut. The widea open throttle trick don't work on rev limited saws


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## bikemike (Sep 20, 2015)

It's the freaking weekend we need to see ur progress on ur saw


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## Brushpile (Dec 6, 2015)

I just figured I'd post my video of my modded CS-400 with a new WoodlandsPro 16" bar, and Carlton semi-chisel low pro chain, cutting some cedar cookies for my wife. She wants them for stepping stones in her garden, or who knows what, but I was happy to oblige her.


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## stubnail67 (Dec 6, 2015)

sounds a lil rich?or coil?like that bar and chain....I mean it does not seem to be cleaning up in the cut..... maybe i my ears are bad some one will chime in......


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## BGE541 (Dec 7, 2015)

Maybelean out a hair more but Ican hear it start/clean up into the cut... good sounding muffler mod, sharp little saw! Had a reconditioned one at theHomeDepot here for $200...


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## Idahonative (Dec 7, 2015)

bikemike said:


> You have to remember tune after any mod or weather change no caps makes it easy. Tune it in the cut. *The widea open throttle trick don't work on rev limited saws*



Actually, tuning my 600p, WOT, at 12,300-12,500 is the sweet spot for power/torque. That is still below the rev limiter.

EDIT: That saw only has a MM and tab delete.


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## BoBDoG2o02 (Feb 11, 2016)

@RedFir Down , thanks for your time to post on this. I just got done with the limiters and gutting the muffler, ill post pics later. I was fairly concerned about the limiters until reading this post. Found out my saw was as fat as possible when i started aligning the limiters for removal. Until today i havent touched the screws.


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## BoBDoG2o02 (Feb 11, 2016)

Is the coil on the CS-400 rev limited?


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## Ozarker 1 (Feb 11, 2016)

I asked Echo about the rpm at which the rev-limiter kicked in on the CS-400. Here's the answer: "The coil engages at approximately 15,000 rpm."


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## RedFir Down (Feb 11, 2016)

BoBDoG2o02 said:


> thanks


Your welcome. Glad you found it useful.



BoBDoG2o02 said:


> Is the coil on the CS-400 rev limited?


To be honest with you I dont know. I have removed the CAT's on a hand full of these 400's and never put my tach to any of them, I just tuned them in the wood.


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## Eagle_Adam (Jan 15, 2019)

Full Chisel said:


> This video will help you get your saw tuned. Keep in mind your Echo has a limited coil so it will sound like it's 4 stroking when it hits the limiter. Richen the H to where it doesn't drop much RPMs off full throttle when the limiter kicks in...there is a slight delay after it spools up, you can hear the difference. It's best to tune in wood, richen it up to where it burbles heavy in the cut and lean it out slowly to where it cleans up but still burbles when you let up on it. But definitely get those tabs off and richen it up some.


. Thank you much for this vid, oddly enough I can tune a car with a carb(or two or three) no prob..... And yet until your vid I hadn't felt confident in my diagnosis of the diff between 2 and 4 stroking


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## jrs_diesel (Feb 1, 2019)

Ozarker 1 said:


> I asked Echo about the rpm at which the rev-limiter kicked in on the CS-400. Here's the answer: "The coil engages at approximately 15,000 rpm."



I wonder why they gave you that number?  It directly contradicts what is written in the CS-400 manual , which lists the following for RPM's:

2,650 RPM - Idle speed
4,050 RPM - Clutch engagement speed
12,650 - Wide open throttle speed


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## s sidewall (Feb 1, 2019)

Wonder if that working rpm @ wot?

Steve


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## James Miller (Feb 2, 2019)

jrs_diesel said:


> I wonder why they gave you that number?  It directly contradicts what is written in the CS-400 manual , which lists the following for RPM's:
> 
> 2,650 RPM - Idle speed
> 4,050 RPM - Clutch engagement speed
> 12,650 - Wide open throttle speed


Wide open throttle would be working rpm. The limiter kicks in at 15k. Try to cut with it set lean enough to tag the limiter and I'd bet it wouldn't survive the first cut.


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## SierraMtns (Feb 2, 2019)

James Miller said:


> Wide open throttle would be working rpm. The limiter kicks in at 15k. Try to cut with it set lean enough to tag the limiter and I'd bet it wouldn't survive the first cut.



Isn't there a lot of variables with working rpm's? Chain grind, bar length and the amount of pressure the person is putting on the saw are just a couple that I could think of. 

I would think Echo would have that saw setup with no load wide open speed out of the wood.


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## jrs_diesel (Feb 2, 2019)

Only way to know for sure would be with a tach. 

Though thinking about it, 15k would sound like a real screamer. And Echo’s seem to be built more towards mid range power than top end rpm.


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## s sidewall (Feb 2, 2019)

Here's what my manual has, as of 11/09.






Steve


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## Deleted member 149229 (Feb 2, 2019)

s sidewall said:


> Here's what my manual has, as of 11/09.
> 
> 
> 
> ...


I have what Steve has. 15,000 grand would sound like a blender, right before it melted down like the reactor at Chernobyl.


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## s sidewall (Feb 2, 2019)

You've got proof of that don't ya

Steve


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## Deleted member 149229 (Feb 3, 2019)

s sidewall said:


> You've got proof of that don't ya
> 
> Steve


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## jrs_diesel (Feb 3, 2019)

My service manual shows the same RPM range Steve. Very close between the owner's manual and the service manual.

Reading further in the service manual under carb tuning, they have you start at about 11,500 RPM on the rich rich and to lean from there to hit max RPM to adjust the H screw.


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## s sidewall (Feb 3, 2019)

Ran mine today, definitely don't sound like 15,000 rpm to me. Don't know how or why echo would have told him that.

Steve


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## Colt Marlington (Feb 3, 2019)

I knocked the cat out of my 346 muffler with a scrench and a hammer.
Pulled the big pieces out with a leatherman.
Then chiseled all the edges clean with the scrench and hammer again.
Shook it until nothing else was rattling around inside, reinstalled, and then put the screen and deflector back on.


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## James Miller (Feb 4, 2019)

I use a 1" holesaw bit in a drill press. The a flap wheel to clean up the little bit that doesn't get. Rinse with hot soapy water till clean. Never done a 346 but it works well on the 310-400 saws.


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## Colt Marlington (Feb 4, 2019)

A hole saw won't fit in a CS-346 muffler. It has a small rectangular hole.


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## Jonny460 (Jun 27, 2020)

Most of the CS 400 on my tach come in right around 11800 and 12600 approx, I made a mistake stupid leaned out when I was supposed to richen and saw went screaming and my high RPM only showed a max of 13900, I don’t want that to happen again luckily only there for a split second but wow they scream, add another 1100 rpm I could for sure hear one of these come apart at 15000 rpm which just sounds crazy once you hear almost 14k, if it goes to over rev you don’t need a tach, the saw will let you know because they truly scream


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## jp233 (Jun 27, 2020)

they can all scream for a second at that high rpm, just back it off quick. and it's best to let it cool down after, if you did it a few times while tuning, and if you can. If you're tuning in the woods and have to keep cutting, would be worth a couple minute break if you went to hard at it. the balancing act of RPM in the wood vs. fuel/mix charge getting into the engine to lubricate, combust, and cool is the dance we all love to do.

Ole' Buckin Billy Ray Smith has a good video on this, for the high-side adjustment you can skip to about 15:40 of the video


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