Chain idle issue

[Gavin]

Hi,
My Stihl 029 recently has developed an idle problem. I wouldn't  idle low enough to stop the chain.

It defied adjustment on the idle screw and the H/l tuning screws. 
 
After much investigation -cleaning -air leak searches - etc  I decided it was a low speed mixture issue or an undetected air leak.
  
The easiest option was to replace the carb -all rubber -fuel filter and plug.

The new carb-- factory set and with new rubber--- it does the same.

I silicon-ed the carb to rubber interconnect because I though it could be a leak source.

I can get the saw to idle poorly by opening the (1.025) idle screw but its about 2.5 -3 + turns open so should be very rich.

I conclude at this setting its making up for an air leak, it also wont rev out and has no power.

Now the question would engine crank shaft seals do this, how do you test these?
Can they be replaced  without splitting the engine?

r
Gavin

 

[sawguy21]

You need to pressurize the crank case with a Mityvac tester to check for leaks. Can you remove the clutch and check for grass or other debris in the seal?

[ladylake]

 If it idles at all take the clutch cover off and spray some WD40 or similar  at the seal area, carb boot or any area where it might leak air.  If the saw slows down you found the leak.   Steve

[Gavin]

Thanks for replies,
I pressurized the Crankcase after logging my email and found it would not hold pressure. On further stripping I find the bottom casing is cracked and one of the four mounting bolts is sheared off, (the bolt by the chain mount.) It has obviously got jammed and considerably loaded up to do this. (Not by me) 
probably just before it stopped idling properly this happened. Question is now can I buy a new crank case and is the saw worth it/
Thanks for the forum comments.
R 
Gavin

[mike_belben]

IMO the farm boss clamshell platform isnt really worth expensive new oem parts.  The clam seal always seems to fail on me.  They are popular however and i have made good money buying siezed ones, fixing and flipping.  

I am not a fan of stihl at all, i consider them a pain to work on compared to husky.  In stihls defense it is designed to be a cheaper mid level saw that competes with husky 350/450/jonsky CS21xx etc and they arent free from shame either.  The husky mid level stuff either loosens the muffler and melts the oil tank or gets a leak at the plastic junk carb boot.  


Pick your poison i guess! 

[Gavin]

I have decided to repair this saw with after-market parts -new crank case pan and new engine mount plastics -its cracked also. I will replace the bearings and seals while out. 
Can anyone advise the torque settings for the four pan bolts and the chain bar studs? 
Gavin

[Al_Smith]

Google will tell you the torque specs on metric bolts .For example M6 lubed in aluminum is 4 Ft lbs .
As far as a half-fast fix ,because it's low pressure Locktite 5900 will seal just about any leak if the surface is clean .Acetone is a good cleaner .
Nothing wrong with an 029,they made millions but they are not the most robust saw ever made .I've got a box full of parts from same that could not with stand commercial use in  the the tree service business .They got about a year and half out of them .Yet on stuff like firewood for the average user they do just fine .

[Real1shepherd]

I am not a fan of stihl at all, i consider them a pain to work on compared to husky.

Ohhhhh.....that's heresy here in Squeal country..... 8)


I always urge people to spend a little more and buy a pro quality saw. They will usually last a homeowner/weekend warrior his/her life.


Kevin

[Al_Smith]

A clam shell Stihl isn't hard to work on .I mean the whole thing comes apart by removing a few screws .It's not like splitting the case on a pro model with heat shrink fit bearings .
I've only repaired a few ,029-039 series and that was with used parts I found in my parts boxes .Maybe new seals and Permatex number two .Permatex came from the days of the model T ford and still works today very well .
I have no interest in owning one there fore have not visited E-bay for used parts but would suggest they are readily available for a modest price compared to OEM .  

[Gavin]

Thanks for the advice on the 029 Crank case break.
I think I brought a saw that has seen abuse.
One more question.
Is the cracked engine housing(plastic)    -around one of the Clam shell bolts (4 off) a common problem in the 029?
One of the other bolts -by the chain studs had a sheared off head.
I wonder what was first?

This is about $US 120 worth of parts even with aftermarket! But the bore is fine and the rest new.

R 
Gavin

[mike_belben]

I was a machinist and engine builder.  Splitting cases doesnt bother me at all but putting the carb back on a 270/290 makes me wanna throw it.  I have a horrible time getting my fingers in there.  Ive ported quite a few saws, cut jugs on lathe jigs, welded pistons, epoxied crankcases...  Its not that i cant.  I just hate the farmboss.  Runs good when it runs good.  Expensive piece of junk when it melts down.  MS260 pro.. Joy to work on.

[joe_indi]

There is nothing to sniff about just by virtue of the 029 being a clam shell /short block type
It has been designed for taking a lot of load and punishment just like the professional saws and can handle bars up to 24" in a pinch
But, it is not a pro saw intended for 24 x 365 kind of application, but to work like a pro saw on a farm.

Its clam shell may seem awkward for the saw mechanics, but once you know the the 'how' and sequence of steps, it is a fairly simple saw to repair. 
And it has a heavy crankshaft for the high mid range power it has. And to handle the punishing crankloads that may happen in the hands of the average farmer, the crankshaft rests on bigger 6203 bearings, while most pro saws use smaller 6202 bearings. 6203 bearings are what come on 80cc plus saws. So you can get idea of the punishment tolerance the 54 cc 029 has.

The main con of its clam shell design is unlike smaller clam shell that have  4 screws for for keeping the pan and cylinder tight and another 4 screws for holding the engine block in the body, the 029 has just four screws to do both these. Since the screws are in metal sleeve inserts, there is a limit to how much the screws can be tightened. Heat or a slightly loose screw could compress the non metallic area where the screw seats creating a clearance. This will result in the screw being tight but loose in the body. Also, the screw splines can no longer lock into the body and vibrations will loosen them whatever thread locking compound is applied.
But, there is a simple solution for this. If you notice a screw is loose on the body even though it is fully tight in its thread (This is detectable by the gray to blackish color around the screw from vibration) all you have to do is take out the metal insert and grind it down so that its level is below the body when it is pressed down in place. About .5 mm is ideal.
Except for this Achilles heel the 029 and its siblings in the 1127 range are great saws for farmers and weekend warriors.
Torque settings and other settings are provided below.

 

 
Joe

[Gavin]

Thanks Joe,
That is a great confidence boaster for the old  029.
 I thought it was a good saw when it was running properly, Plenty of power when driving a 20 inch bar and not too heavy. I will obtain parts and rebuild it. Thanks for the torque figures.
Regards
Gavin  

[Spike60]

Like Mike and Kevin, I'm certainly not a Stihl guy by any stretch. Since I won't even take them in for repair, that lack of familiarity really does fuel the "hate to work on them" attitude. For regular Stihl guys it's probably not a big deal. Joe is really spot on about the "sequence of steps" being important.

I never think of any of these clamshell saws as being worth a major rebuild effort. OK if you can use parts from other dead saws, but not so much if you have to lay out for parts. (And never in a shop with the labor clock ticking.) Add in the lack of consistancy with aftermarket parts and you never know where you'll end up.

[Soundsilent]

This may be a silly suggestion, but fuel supply good?  By that I mean are the fuel lines in good shape?  My neighbor brought me a saw he sent to a shop that acted similar.  New carb, still no fix.  Shop charged him anyways.  I got lucky and found a bad intake(supply) fuel line.  Sometimes we focus so much on one point, we are oblivious to the rest.

.02

[Gavin]

Thanks for all the good advice on my 029.
 I have the parts -mostly -and was about to begin reassembly.
  However the pan bolts received are much finer thread. I note on some parts sites the reference is -this replaces xxxx. 
  The original screws have about 16 threads and are 1.6 pitch the replacement are approximately 1 similar to 6mm metric. 
I had one sheared off (caused the pan breakage) and I thought this was unusual or was the result of rough handling.
I now note from some of the site comments this occurs and could be aftermarket "soft" screws.  I also tested the bolt torque required (Had thought "thats high")  but found it OK.  
 I am reluctant to use the fine threaded screws substituted  unless some one has experience of this and have used this fine self tapping screws in old holes. 

[Gavin]

Round this subject off--- with the  029 saw -with the new engine pan - is up and running.  The pan bolts fine thread or original  coarse thread -work fine.
 I will pay closer attention to crank shaft sealing on small engines in future as this makes a big difference. 
 I thank the forum for the many comments.