026 Pro Cutting Out w Brake

[logbutcher]

The "almost perfect saw" is behaving like a bad boy.

This Stihl 026 Pro with a high / low adjustable carb, clean filter, new plug, clean high test mix, and sharp chain is cutting out/stalling when pulling the chain brake off. Unless I goose it slightly while letting the brake go, it will stall. All adjustments seem to be normal when warm. :
I've tried increasing the idle but don't want the chain to creep.

Explanation is in order. I never used a chain brake under normal use before training in GOL (Game of Logging) and CPL ( Certiied Pro Logger). Besides full PPE (Personal Protective Equipment), I follow guidelines in that program that make safety sense such as chain brake on when moving more than a couple of steps with the saw idling. It works especially in thick blowdowns and brush.( No, I don't belay on the ground.....yet. ;D )  The training also recommends always starting with the brake on. Use of the brake now is second nature in my cutting, clearing, bucking, TSI. Long winded here.... :-[

So, what would cause the engine to die when 'pulling' the chain brake off ? Anything specific that I can adjust, check ?

[jokers]

Try richening your lo speed needle.

Russ

[logbutcher]

Already done the lo to rich and richer.
" Can't be too rich or too thin."  :D

[Kevin]

It may also be restricted fuel anywhere from the vent to the carb or leaky carb gaskets at the intake port.

[Rocky_J]

Actually Russ, I was thinking just the opposite. A slightly rich low end adjustment will cause a saw to load up with fuel while idling and then stall out when the throttle is hit. I read a good way to check this on the 'other' forum- let your saw idle for a few minutes and then turn it upside-down. If the low speed jet is too rich, it will stall from all the extra fuel in the bottom of the motor getting dumped into the cylinder.

[logbutcher]

Will do both: upside down check, vent hose, gaskets.
Neat ideas as usual !  Thx guys.

BTW: are Brian and Russ twins?  Curious minds want to know ...    ??? Dopelganger or something?

[Rocky_J]

No, Russ and I are not twins. I'm much smarter and better looking than him.
 8) 8)

[tony_marks]

  just curious .. do u start it with the brake on... i know they saythats safer and everything . but i dont do that.. never have..
  do u guys all start u saws with brake on.. some of mine would be a bear to start that way.. just curious..
   rocky and joker ,twins.. now thats a good way to get both ofum mad atchu. :D

[logbutcher]

Lunch break.

Contest idea: who's the best looking online. Virtual cheesecake. Maybe even : The Great Nude Chainsaw Finale.
The "how do I look in chaps, gloves, helmet...without anything else" contest .  :P    We could even have a special forum.

Tony: the " brake on " method is  protection from the infamous "drop start" that we all (past tense) have used. Many many slicings from a high torque saw at rev speed hitting soft flesh w the drop start documented. The official GOL/CLP start is w brake on, then start it with the saw between the thighs (no comments here kids !  8)   ). You have complete control of the reving saw. Alternative is to start w your tiny boot in the handle on the ground...not always possible on tough terrain.
Brake on when moving anywhere w a running saw, or shut it down  Later is usually impractical for most of us. No one of us has fallen when walking/running/ambling w the saw running.. ...right ? : .

BTW: changed the lo needle to slightly rich. No effect right up or upside down. Gaskets 'seem' to be OK. Vent open.
Still trying. Thx. Tak tak.

[Kevin]

Maybe a little carb cleaning?

[oldsaw-addict]

If you cant figure it out, then I would suggest taking it to the dealer for service. It sounds to me like the issue is something to do with the fuel mixture needles, maybe the H is too rich or lean, when you go to rev it up, does the saw just stall the instant you go to rev it or does it get to slightly higher rpms then stall? This should help me get an idea of how I could help.

[firtol88]

Lunch break.

Contest idea: who's the best looking online. Virtual cheesecake. Maybe even : The Great Nude Chainsaw Finale.
The "how do I look in chaps, gloves, helmet...without anything else" contest .  :P    We could even have a special forum.

That sounds like the single worst idea I have heard in quite some time. ??? Don't know about you but the [size=52]LAST[/size] thing I want to see is a man's hairy butt.

[oldsaw-addict]

Amen to that. I dont want to see a mans hairy backside any more than anyone else here does.

[jokers]

Actually Brian and I are twins, although he is the smarter and more handsome evil twin.  :D

Brian,
I follow your logic but I believe that Logbutcher stated that the saw dies if he DOESN`T gas it when releasing the brake. My line of thinking is that he is masking an ultra lean condition by feeding the saw off the hi speed circuit. Might also be a crank seal.

Russ

[logbutcher]

"...masking an ultra lean condition by feeding the saw off the hi speed circuit. Might also be a crank seal. " Jokers
Some explanation and solution here?
Saw runs super--accelerates smoothly up to WOT, idles fine.
Only problem when 'pulling' the brake off for continued cutting. I do this a lot in blowdown clearing. End result to bring brush and trunks to ground for moving.  The saw then will stall at idle while the brake is being pulled 'off' unless goosed. All when well warmed up. Still trying and thx for the advice.


Whew: some of you people are sensitive about hair !!!   ::)This is a "chainsaw" forum after all. We're talking "nude" here, not "backsides" IMHO.  ;D   And you there firtol88, you're first. Runway will be on 31 Dec, 2004, 10th Mountain Division Winter Sports Center, Fort Kent, Maine. RSVP.

[Stan]

That sounds like the single worst idea I have heard in quite some time. ??? Don't know about you but the [size=52]LAST[/size] thing I want to see is a man's hairy butt.

Some of us are a bit further along the evolutionary path, and don't have hairy butts.  :

[SasquatchMan]

Speak for yourself Stan.  I grow better hair uncultivated on my butt than you can grow cultivated on your head. ;)

Am I misunderstanding something here - what on earth does disengaging the brake have to do with the running of the saw.  If the saw runs with the brake on, clicking it off shouldn't affect the saw - unless some internal brake component is malfuncioning?  I know the brake in my MS290 is "internal"... could the brake be affecting the clutch?  That would stall er out in a hurry.

[Stan]

Speak for yourself Stan.  I grow better hair uncultivated on my butt than you can grow cultivated on your head. ;)

Then you have chosen your handle well. When he takes the brake off, the saw stalls because the load has been suddenly removed. I don't know why that makes it stall, just that it does. Sometimes when I take my foot off the brake on my wife's van and don't get on the gas, it stumbles.

[SasquatchMan]

When the brake is on at idle, the clutch is disengaged.  When you remove the brake, the clutch remains disengaged, if all things are working right.  

So where's the load differential?  There isn't one.  Which is why I can't figure this as a mix issue, but rather as a mechanical one.

[Rocky_J]

If the chain is trying to spin when the saw is at idle, then either the idle is too high or else the saw has a broken clutch spring.

[incognitive]

I'm prettier than either Rocky or Jokers, and they can attest to that since they recently, finally, got to see me.  I haven't seen a pic of Jokers, but anybody that kicks sand like he does has to be mad about the way he looks.  (shh!, at least for a little while, ok?)

butcher, this sort of problem is exactly the type of stuff that interests me.  I'd like a little more concise detail, particularly regarding:

• are you saying that merely the act of releasing the brake causes the engine to stumble?
  
• when the saw is idling without the brake and at the moment you engage the brake is there any change whatsoever in the way the saw's operating other than now the clutch drum is locked?
  
• assuming the first point is true, does it matter in what manner the brake is released?
  • saw sitting on ground
  • saw in the air, left hand removed from front handgrip to pull back on guard while supporting saw only by rear handle
  • same, but also supporting saw against thigh
  • saw in the air, left thumb supporting front handgrip while pulling back on guard with left finger(s) (essentially the same as item above while supporting saw on thigh)
  • saw in the air, supported by front handgrip in left hand, brake release by right hand
  I guess what I'm getting at is, if the mere act of releasing the brake is instigating the stumble, there must be a marginal electrical connection (least likely) or some physical property (defect) of the saw which is being particularly influenced by the action.  I can't figure what it might be though, that wouldn't also be a factor in almost any situation the saw would be at some point during normal use.  
  
  If it were, say, an isolation bushing being out and allowing the pulse hose to be pinched off against the rear handle as you pull the guard back with your left hand while holding the rear handle in your right or something.  Or maybe a cracked pulse hose being opened momentarily during the same action.  Why wouldn't you ever run into it at some point during normal use?
  
  Try the various methods of brake release and report back any differences in response.
  
  I highly suspect it's not got anything to do with jet or metering valve settings inside the carb.  Rather some wire or hose or boot being influenced in a negative way.

[logbutcher]

OK, it is "hoosier", as in : " hoosier moma, hoosier fatha" ? :

Incog has given some serious details needed. Will do during tomoro's cutting.
Some prelim replies:
Yes, the engine slows to stall in the act of releasing the brake in a slight down angle close to the right thigh.
Yes, there is a slight "stumble" in the engine when engaging the brake with a flick of my forearm downward.
I will try all five of the saw positions when engaging/releasing the brake.
And what is a pulse hose ? Where to check ?   :-[
Interesting eval of a problem Herr Hoosier. Have you rock or ice climbed in another life ? Analogous problem solving en routes.
Thx all........very invaluable info !!    8)

[incognitive]

The (im)pulse hose connects to the crankcase and drives the fuel pump diaphragm on the carburetor.  If it's marginal, it might, when flexed, cause poor fuel pressure and/or directly allow air into the crankcase; both resulting in a lean condition to various degrees.  Such a problem may be more pronounced at idle where there isn't enough rotational energy to carry through a temporary glitch.  I should think it would be evident either way, though.

Hoosier like in resident of Indiana.  And no, not an ice climber, though I had a good friend out in Colorado who was.

[Jeff]

Just a reminder fellas. This is the Forestry Forum. We have a record of being A friendly family site. We are listed several places as an educational resource. Lets stay on the tasteful side of things. Nothing here I would delete or edit, just a reminder for the new guys though, The forestry forum's chainsaw forum is your kinder gentler chainsaw forum. A chainsaw forum for EVERY one.

O.K. I had my say. Go ahead and shave or what ever it was you were all doing.

[jokers]

.... The forestry forum's chainsaw forum is your kinder gentler chainsaw forum. A chainsaw forum for EVERY one....

A chainsaw nut safe haven.  ;D

Jeff and Kevin have done an exemplary job of keeping this forum laid back and friendly, it`s a pleasure to come here and kick back.

Russ