Reason for engine revs up when held on side or down/upwards - Stihl MS211

[MartDalb]

Hey everyone


Quick question.

I have a still MS211 - that for, no obvious, reason revs up when put on side or held down/upwards.

It actually runs fine, and also idles at it should, but when I turn it too much down or upwards, it revs up on its own.

I have checked fuel lines, hoses etc. and can't seem to find any obvious reason to this issue.

I do however notice, that I am not able to actually set the "idle", it actual does nothing or near nothing to turn the LA screw.


The saw is not old or mistreated in any way. It is from 2011 and not overly used.


Tips, ideas?

Thanks for all help

 

[ammoaddict]

Air leak is my first thought but I'm no expert.

Sent from my moto g(7) power using Tapatalk

 

[Mad Professor]

Sounds like air leak. Seals air boot or impulse line can be effected by saw position.

Get a pressure/vacuum check done on it.

 

[MartDalb]

Ok sorry I forgot that part.

Yes. I did figure it was a leak.
Maybe I should be more specific.

What places would be more likely.
Fuel hose?
Impulse hose?
Manifold?
Primer bubble and hoses
Or... Oil seals?

I Would be extremely surpriced if oil leaks have gone bad. It's not used alot, and it's been run for forewood and minor trees here and there.

 

[MartDalb]

Sounds like air leak. Seals air boot or impulse line can be effected by saw position.

Get a pressure/vacuum check done on it.

How about carburator, would that do this?
Ill go through it all, but it is very nice to have some tips on the go.

Still surpriced it runs as it does, if I didn't turn It, I would not have noticed at all.

 

[irhunter]

It sounds like your saw is failing what we call a "dump test." Check out Page 3:

https://www.nwcg.gov/sites/default/files/training/docs/rt-130-2012update-iwfm-field-guide.pdf
Does your owner's manual describe how to adjust your carb?

Roy

 

[ironman_gq]

crank seals will cause that. If it's changing rpm's when turned on one side or the other I would suspect them. Regardless it might be time for a leak test.

 

[MartDalb]

going through every little detail, I came across checking why the Carb LA screw won't do anything when turned.

I noticed that there is a slight "slack" in the spring torsion, from the throttle lever on the carburator.
It does not pull the air valve all the way back to sit on the "LA" screw.

Ill explain with pictures from the IPL and Service manual.
The red arrows, indicate that there should be a small metal "notch" that rests on the valve lever.
On my carburator, that little piece is not there, it seems to miss that little piece of "spring" that should rest in the lever.
The spring is there, but may it have broken of a tiny bit?

See pictures, and on my photo you can clearly see that it does not "rest" back onto the LA screw, and if you have good eyes, perhaps it's visible that there is no "notch" onto the lever.


Any help is appriciated here

 

[dmb2613]

crank seals X2 and I know what the hell I am talking about , no armchair quarterback here

 

[MartDalb]

crank seals X2 and I know what the hell I am talking about , no armchair quarterback here

I will find out if it is the seals, I would be very very surprised.
Have not seen a saw with this little use have faulty seals, but I guess it is possible!

 

[MartDalb]

id love a comment on my "spring" torsion theory if possible. There is obviously something not right when the air valve is not being pulled back corretly/enough towards the LA screw. Would this actually cause the idle to jump up and down when I turn/lift the saw?

 

[Mad Professor]

id love a comment on my "spring" torsion theory if possible. There is obviously something not right when the air valve is not being pulled back corretly/enough towards the LA screw. Would this actually cause the idle to jump up and down when I turn/lift the saw?

Fix/replace the spring if it's broken.

 

[MartDalb]

Fix/replace the spring if it's broken.

Yes I will do this.
But...Trying to imagine if this is actually the sole reason to the engine issue.

I mean, the air valve isn't closing down to its "seat", and it is, atleast, semi moveable just by slight touch.

 

[Short timer]

Yes I will do this.
But...Trying to imagine if this is actually the sole reason to the engine issue.

I mean, the air valve isn't closing down to its "seat", and it is, atleast, semi moveable just by slight touch.

Whatever you do, don’t be cutting with it, if it’s an air leak, you’ll burn this saw up real quick.

Replace the suspect part and see if it fixes it.

 

[Okie]

Sometimes you can get a hint if it's the clutch side crank seal by loosening or completely removing the chain. If loosening or taking the chain off changes the idle any at all or kinda cleans up the roll tilt test you have a clutch side seal leaking. I've seen them leak and the bearing still be good, no visible crankshaft side play. the edges of the seal be just dried enough that would leak little air when the chain is tensioned and when the saw is tilted the in/out end play of the crank will allow a seep/leak.
A 3-5 psi pressure test will most generally confirm such as the crankshaft is turned or wiggled while block is pressurized.
I've seen some saws run and the low speed jet adjust good with no chain but get completely erratic after chain tensioned.
Make a feller want to cry sometimes, thinking he has the saw ready for a test in the wood and then see such.
Patience is your friend.

 

[MartDalb]

Whatever you do, don’t be cutting with it, if it’s an air leak, you’ll burn this saw up real quick.

Replace the suspect part and see if it fixes it.

That is the part that makes me think this is NOT an air leak.
My old dad, who has been running it, have not mentioned anything but, "it ran a lil weird"

I have checked the piston, both ends and it's fine and smooth.

I would still say, I will be extremely surprised if it's a regular leak from manifold/Impulse/oil seals.
It's 9 year old, used for fire wood, and its still on it's first original Bar.

I have seen 20 year old 026s etc with no issues at all, and much much more use than this one.

Hoping I have found the issue

 

[Short timer]

That is the part that makes me think this is NOT an air leak.
My old dad, who has been running it, have not mentioned anything but, "it ran a lil weird"

I have checked the piston, both ends and it's fine and smooth.

I would still say, I will be extremely surprised if it's a regular leak from manifold/Impulse/oil seals.
It's 9 year old, used for fire wood, and its still on it's first original Bar.

I have seen 20 year old 026s etc with no issues at all, and much much more use than this one.

Hoping I have found the issue

You could probably rig something up to hold the butterfly against the idle stop to prove your theory, wire it or something like that.

 

[dmb2613]

I will find out if it is the seals, I would be very very surprised.
Have not seen a saw with this little use have faulty seals, but I guess it is possible!

Saw is 9 years old, I expect it has had the brake left on a time or 2 also heat will kill a seal pdq along with age.

 

[PV Hiker]

Replace, repair the broken idle stop. You can't get the saw tuned with this defective.

Do a vacuum and pressure test to check for air leaks.

Do a carb rebuild replacing the 9 year parts inside also throughly spray carb cleaner in all passageways. Replacement of needle and adjust needle arm properly, use new diaphragm. Do pressure check on needle seat, might do test first to see if seat is leaking.

Had a 026 that would race when tipped around ended up working through carb rebuild and properly tuned cured issue. There was no vaccum or pressure leaks. Just getting too much fuel.

But yours might have a air leak you'll need to work through and do the testing. Might as well check coil gap, sparkplug, air filter, fuel filter, rubber hoses, and intake boot.

 

[MartDalb]

Thanks for All the great feedback! I Will start working.