Noob here....basic questions on ECHO CS-400 Chainsaw

[greendohn]

I haven't removed the limiter caps on mine yet. I have richened it up and run a couple dozen tanks thru it. It's something of a mutt and and seems to struggle with a 14" b/c. I only use it for busting brush/limbing and it handles that well enough, just gotta stick to small stuff. I had a 12" b/c on it and it was a beast but I found I was breaking a lot of chains...I've never had problems breaking chains on any other saw.
I'll get around to a MM and eliminating the limiter caps sooner or later,,I had great results doing a MM and proper tuning on a lil cs ?306? which I gave to my twin brother,,it prolly still has the same fuel in it, waiting for him to call askin' what's wrong with it,,it won't start and run!!LOL.

 

[FergusonTO35]

Whoops, sorry for the duplicate post. I noticed that the limiter caps on mine are a rubbery material and actually turn quite easily. Whats the best way to remove them? Can it be done without removing the carb? Given that a small screwdriver fits the caps perfectly I would prefer to modify the caps so that they turn fully and then put them back on.

 

[Hedgerow]

Whoops, sorry for the duplicate post. I noticed that the limiter caps on mine are a rubbery material and actually turn quite easily. Whats the best way to remove them? Can it be done without removing the carb? Given that a small screwdriver fits the caps perfectly I would prefer to modify the caps so that they turn fully and then put them back on.

Are their little tabs on the caps themselves that prevent them from turning any further?
If so, you can just melt the tabs flush with the caps with a solder iron, and turn freely.
Or nip them with cutters, or grind them flush with a thin dremel stone.

 

[FergusonTO35]

Today I modified the limiter caps to allow full movement. Really it was pretty easy. I removed the top cover and recoil housing for clearance. The caps are surrounded by a close fitting metal frame, I pried it out with a small pick tool. With the same tool I pulled out the limiter caps. I trimmed the caps to permit full movement, then reinstalled them and the metal frame that surrounds them.

I tried the saw out on a fallen tree near my house. The low screw required a fair amount of opening, the high very little at all. I can see why Echo installs a rev limiter, this saw would rev to the moon if given the chance. In wood performance was great, this saw will really make some chips in a hurry. One thing I noticed is, like my SRM 225 weedeater, acceleration and deceleration feel more like fuel injection than carburetion. When you pull the trigger there is a split second lag then acceleration. Like wise when you let off there is a pause where the rpm's sort of hang for a bit on the way down. Carb adjustment doesn't affect it. Maybe this is a design characteristic due to having a catalyst. Anyway I'm quite pleased with this saw, well worth the $155.00 I spent.

 

[mountainlake]

Both the hanging idle and hesitation point to a lean setting most likely the low but could be the high. If opening the low or high doesn't help you might have a partially clogged carb. Don't be afraid to open either up quite a bit as these carbs are set somewhere around 3 to 4 turns out to run right. When running right there is no hesitation or hanging idle on a CS400 Steve

 

[FergusonTO35]

Will do, thanks.

 

[jjhoyt]

Setting L and H without limiters

I greatly appreciate the advice in this thread.
I have an almost-new CS-400 and lost the factory L and H settings when modifying the limiter caps.
Please advise how to set L (and maybe H) from scratch.

One reply said that both need to be about 3 to 4 turns out to be set properly.
Other replies give good advice for setting H.

The manual instructs setting L to obtain smooth transition from low to high speed without hesitation, but please suggest where to start with L after losing the factory setting.

I will set the idle speed screw using a tach, but that is independent from the L screw.
WOT is give as 12,650 in the manual, but I will use the recommended two-stroking/four-stroking technique for setting H.

Thanks in advance.

 

[mountainlake]

Start with 3-1/2 turn out with the low, if it dies when you pull the throttle open it up untl it accelerates good. If it doesn't die turn it in untill it does then back out untill it accelerates good. Then adjust the idle speed. Steve

 

[jjhoyt]

Start with 3-1/2 turn out with the low, if it dies when you pull the throttle open it up untl it accelerates good. If it doesn't die turn it in untill it does then back out untill it accelerates good. Then adjust the idle speed. Steve

Thank you!

 

[Toyboy]

I have a dumb question. When or what year did the saws start coming with the limiter caps? I've never looked at my saws for them. I have 2 Huskys that are 2000 model yr and a Stihl MS170 that's about 4 yr old.

 

[cjtreeclimber]

yeah I had pulled the carb out myself and used peace of metal which I then dremeled really thin to sorta hook out those limiters on my 400 and 8000. I think My 400 is a weird saw now that I opened up the muff and tuned it with wood to cut. Sounds nasty when revving without load but when its warmed up and cutting with the chain sharpened right its really doing its job! A couple things about that saw I'd say is put lock tight on all exterior screws that holds the plastic together , and don't bother cutting brush with it unless you want to practice putting the chain back on alot. I have one friend that has been running the piss out of the little four hundred and it still runs like new. Run the damn saw and pull the plug sometime to see what color you get maybe.

 

[FergusonTO35]

My 400 is tuned really good now, after a fair amount of cutting to get it dialed in just right. She idles all day long and accelerates immediately. For 42cc or so this saw can really make the chips fly. Mine seems to like the low screw turned out around 3-1/2 turns, the high at 2-1/2. I have to wonder, how lean is too lean? I find that if I turn the high screw in about 1/8 of a turn more it cuts noticeably faster, however I'm more concerned with longevity than anything else. I don't have a tach yet, it's on the wish list. Should I turn the screw in a little more for the added performance or just play it safe?

 

[FergusonTO35]

My saw is totally stock. I find there is no real universal carb adjustment for two cycle machines. Too many variables in carbs, atmospheric conditions, engine load, fuel, how much dirt is in the carb, how well do the diaphragms work, on and on. I guess I've been very fortunate in the since that most of my machines were tuned surprisingly good from the factory. Usually all they needed was to turn the idle speed up a little. I wonder if there is a way to determine if I'm running my saw too lean in the cut?

 

[Hedgerow]

My saw is totally stock. I find there is no real universal carb adjustment for two cycle machines. Too many variables in carbs, atmospheric conditions, engine load, fuel, how much dirt is in the carb, how well do the diaphragms work, on and on. I guess I've been very fortunate in the since that most of my machines were tuned surprisingly good from the factory. Usually all they needed was to turn the idle speed up a little. I wonder if there is a way to determine if I'm running my saw too lean in the cut?

If you are in the middle of an extended cut, and you take the load off the saw momentarily, it should 4-stroke "Blubber", then clean up when put back under load. It should be noticeable and repeatable...
Then you know you're getting adequate fuel on the high side...

 

[FergusonTO35]

Thanks, I'll check that out.

 

[FergusonTO35]

Arright, my CS400 is giving me fits. Yesterday it was running perfect. Today, it wants to idle really fast and has noticeably less power in the cut. Adjusting the idle speed and mixture s Rees has no effect. What gives? Did I suddenly develop an air leak? Maybe the carb needs a rebuild already? A quick visual inspection showed nothing out of the ordinary. Advice needed!

 

[Team FAST]

Performance

When you are ready to take things to the next level, check this thread:

http://www.arboristsite.com/chainsaw/129928.htm

 

[Hedgerow]

Arright, my CS400 is giving me fits. Yesterday it was running perfect. Today, it wants to idle really fast and has noticeably less power in the cut. Adjusting the idle speed and mixture s Rees has no effect. What gives? Did I suddenly develop an air leak? Maybe the carb needs a rebuild already? A quick visual inspection showed nothing out of the ordinary. Advice needed!

First check your fuel tank... Make sure there's ample fuel and the filter ain't stuck up in a corner of the fuel tank... Then check the fuel line inside the tank and where it passes through the tank... They can crack. Idling up means a lean condition, so think of all the things that can cause a shortage of fuel... Or air bubbles... Tank vent can also cause problems, but usually only after it runs properly for a minute...

 

[FergusonTO35]

Finally, an update on the CS-400. I determined that the saw had a vacuum leak allowing extra air into the engine creating the aforementioned problems. I figured it would be the intake boot or impulse line, the usual suspects. I removed them and inspected thoroughly, no problems noticed whatsoever and no loose screws or anything. I cleaned the parts and reinstalled them, adding a very thin layer of Tack n' Seal gasket sealer to the gaskets. Got it back together, marveling at the bass-ackwards fuel line routing. Started it up and now it seems fine, idles good and accelerates like its supposed to. I guess somehow I fixed it, will give it a try in wood tomorrow!

 

[FergusonTO35]

Today I gave the saw a try on a big walnut which has fallen down. With some carb adjustment it's cutting like a champ again. The saw starts easily and accelerates just fine, also no drama on a hot restart, just pull the cord and you're running again. I still have no idea what I did to fix it. Maybe the intake boot was not seated squarely on the cylinder or in the plastic frame that connects to the carb. Or one of the gaskets was cockeyed in the first place. I never noticed any problems when I took it apart. Lets just hope it stays this way!