Stihl 029 cutting out...

[Rlundy]

Hello to all and Merry CHRISTmas.

I have 4 chainsaws and my 029 [not MS290] starting cutting out on me yesterday.

First emptied out all the old fuel and fed her 93 octane w premium echo mix. Ran this fuel in 2 others [MS290, HT-101 pole] and they have been performing perfect.

Once I start her up, she runs fine for about 1-2 mins, then just dies. I then would restart and she'd run again but I had to keep throttle wide open, but would eventually die again in 45-60 secs. Then 2-3 mins later, I could start her at idle, but applying any throttle she'd immediately cut out. This happened 2-3 times in a row after repeatedly starting her so I just shut her down...also, the air-filter is not bad at all.

Do these symptoms provide any sure-fire cause/problem(s)? If so, what would you recommend as a solution? Also, I can engage in any add'l troubleshooting, but will have to wait until this friday when I go back to farm.

Thank you in-advance and immensely appreciate your help and suggestions.

Best,
tstex

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Check the spark arrestor

 

[FredM AZ]

I had a similar problem with a Stihl saw. It was caused by an old fuel line on the filter. When the saw would heat up the old line would collapse and starve it for fuel. Took it to several shops and finally one shop found the problem.

 

[mjonesnh]

Have a Husky 142 that had that problem. Fuel line coming from filter to carb had several holes in line, replaced line and no problems since.

 

[Snobdds]

250˚F is well below the melting point of solder. 250˚C would melt most common solder alloys (The common 60% tin/40% lead solder melts at about 185˚C = 365˚F. Most people actually solder at significantly above the melting point to insure a good bond.) Baking at 250˚F might do something (perhaps drive off moisture in the coil?), but I doubt it's reforming solder joints.

I'd be a little concerned about the temperature rating of the insulation on the windings or other components if you got too hot. I have no idea what the ratings might be for those components.

The idea is not to completely melt the solder, it would run away from where it's needed. The idea is to get it hot enough to make it pliable and fill any vibration cracks that may have developed and contributing to the cutting out. The joint is not fully broken, just cracked. This is why it's only recommended to heat to around 250.

It works because of the low heat.

 

[MapleLeafFarmer]

I had a similar problem with a Stihl saw. It was caused by an old fuel line on the filter. When the saw would heat up the old line would collapse and starve it for fuel. Took it to several shops and finally one shop found the problem.

that's my thinking as well when we have saw problems. Hard to diagnose 1 individual problem so when saw acts up we do a cheap "head to toe" first

- the quick and easy stuff first. immediately get new plug, gas line, gas filter, fresh gas, air filter, spark arrestor clean, carb clean. We do this every fall on every saw we own.

if not running better

- carb replace,(Costs a little more at maybe $60 from our local saw supplier) and a coil diagnostic but usually a replace as cost only about $75, full electrical connection clean.

and if it still doesn't purr then out the door it goes to a new home someone who has more patience than I have. The joy of a well running / sharp saw is a truly wonderful feeling. A bad running saw frustrates me behind measure (haha)

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[DGF]

if you find the coil is bad, bake it in the over around 250 for an hour.

The theory is the solder joints in the coil break and the heat allows for the solder to get liquid and reweld itself to the coil.

Hi,

This old school trick of heat soaking in that temp range doesn't work any more. In 1998 the industry began to shift to lead free solder and it's use in equipment other than mostly military ended in 2006 with the RoHs initititive. The new solder requires 450F to reflow. It doesn't need to stay at that temp long, maybe a minute but its hot.

Heat soaking in the 200F range does offer some benefit though. The plastic encapulation is not poruous however the mating surfaces near wires and tabs can allow moisture to creep in and if there is enough it can effect the high voltage coil in a way that it leaks and never reaches the right amplitude. 24 hr heat soaking can drive that moisture out and may help.

To tell if its worth the trouble, run the engine until it quits. Then pull the plug right away and perform an old fashion spark test to see if there is a nice blue-white spark. If not the coil should be replaced rather than trying to dry it out. Replacements are available after market for a lot of saws for around $15-$20 and take only a few minutes to swap out. The money is worth the hassle of trying to get the old one to work. The thing is, even if you bake the old one and it does work there is likely corrosion inside so it will die again and when you need it most on a damp day of course.

 

[Snobdds]

Hi,

This old school trick of heat soaking in that temp reange doesn't work any more. In 1998 the industry began to shift to lead free solder and it's use in equipment other than mostly military ended in 2006 with the RoHs initititive. The new solder requires 450F to reflow. It doesn't need to stay at that temp long, maybe a minute but its hot.

Heat soaking in the 200F range does offer some benefit though. The plastic encapulation is not poruous however the mating surfaces near wires and tabs can allow moisture to creep in and if there is enough it can effect the high voltage coil in a way that it leaks and never reaches the right amplitude. 24 hr heat soaking can drive that moisture out and may help.

To tell if its worth the trouble, run the engine until it quits. Then pull the plug right away and perform an old fashion spark test to see if there is a nice blue-white spark. If not the coil should be replaced rather than trying to dry it out. Replacements are available after market for a lot of saws for around $15-$20 and take only a few minutes to swap out. The money is worth the hassle of trying to get the old one to work. The thing is, even if you bake the old one and it does work there is likely corrosion inside so it will die again and when you need it most on a damp day of course.

The stihl 029 was designed in the late 80's and in production from the early 90's through the late 90's.

This one has lead solder.

 

[joea99]

As cheap as good quality aftermarket coils are just change it. Little Red Barn is not cheapest but reliable. The "heat soak" is old school, you still have an old coil where the insulation is breaking down, etc. Just get a new one, adjust the gap and get on with cutting.

I have an 029 and an 012. Both had the runs good but stops when hot issue. The 012 was the coil after being "Fixed" by a buddy/expert twice.

The 029 was cracked/deteriorated fuel lines but in a few weeks I changed the coil also.

When machines get that old, the rubber is always suspect.

 

[grsthegreat]

Man, my 029 was purchased around 1993…..it just runs and runs. Only thing I had to replace has been the bar and kick back brake when it fell out of the tractor bucket and I drove over the saw…..oops.

Other than basic maintenance like plugs and air filter that is.

I only use ethanol free fuel. The old fuel pickup tubes I’m sure can’t handle ethanol.

 

[grsthegreat]

If I recall correctly… there’s a weighted fuel filter inside the fuel tank. I believe there’s a repair kit that includes a fuel line and filter.

 

[tstex]

Thank you for all the replies / been traveling and once I catch up and have Christmas, I will go out and starting addressing some of the things you guys suggested here / thank you very much and I will post back soon / Merry Christmas to all

 

[TORQUIN]

Another thing I just remembered, the spark plug. I have a Harbor Freight pressure washer with a Predator engine (Chinese copy of a Honda engine). Buddy gave it to me because once it warmed up it just quit and then once restarted, it would run for a short time then cut off again, repeatedly.

I didn't have high hopes due to the Chinese-copy aspect of this engine. I went through the fuel system and could find no problems. I finally changed the Chinese spark plug in it, with a Bosch, and now it runs like the wind. Starts with one pull. I had never encountered this behavior being caused by a spark plug, but apparently spark plugs are more complicated than I thought. Still surprised that is all there was to the problem.

Side note, I am pretty impressed by the Predator engine. Since the spark plug change it has been running great, as good as I expect a Honda to perform.

Chris

 

[big bubba]

You might want to check to see how much carbon has built up in the exhaust.

yes. sometimes the spark arrestor (screen) on exhaust port becomes obstructed. hasn't happened on my chain saws, but blowers & trimmers once in a while. i just remove the screen.

 

[tstex]

I have an MS290 that, once it starts, it has a "dead period" after running for about 15 seconds. It wants to cut off, and will, unless you power through by holding the throttle wide open. Once you get through that, it runs and idles fine. It's like it has a bubble in the fuel line and there is no buffer in the fuel bowl, so it runs out of fuel for a second.

As far as your symptoms, have you checked to see that it has spark when it cuts off and won't start? Immediately checking this will tell you if there is an ignition problem.
When it cuts off, is is cutting off from an idle?
How does it run a half choke, after cutting off?

Chris

As far as your symptoms, have you checked to see that it has spark when it cuts off and won't start? No, I have not had a chance to do any troubleshooting yet.

Immediately checking this will tell you if there is an ignition problem. check

When it cuts off, is it cutting off from an idle? No. It only cuts off under 2 conditions so far: when it has the throttle open to various speeds and has been running for a min or so...then after running for a short period and cuts off, I can start it again, and when idling after start up, if I attempt to throttle her any, it immediately cuts off.

How does it run a half choke, after cutting off? Have not tried

 

[big bubba]

remove muffler, see how it runs, check fuel cap for venting & of course assume you've replaced plug

 

[RVAWeekendWarrior]

Hello to all and Merry CHRISTmas.

I have 4 chainsaws and my 029 [not MS290] starting cutting out on me yesterday.

First emptied out all the old fuel and fed her 93 octane w premium echo mix. Ran this fuel in 2 others [MS290, HT-101 pole] and they have been performing perfect.

Once I start her up, she runs fine for about 1-2 mins, then just dies. I then would restart and she'd run again but I had to keep throttle wide open, but would eventually die again in 45-60 secs. Then 2-3 mins later, I could start her at idle, but applying any throttle she'd immediately cut out. This happened 2-3 times in a row after repeatedly starting her so I just shut her down...also, the air-filter is not bad at all.

Do these symptoms provide any sure-fire cause/problem(s)? If so, what would you recommend as a solution? Also, I can engage in any add'l troubleshooting, but will have to wait until this friday when I go back to farm.

Thank you in-advance and immensely appreciate your help and suggestions.

Best,
tstex

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Sounds like it's running a little rich. Hard to tell without hearing it. I'd try adjusting the carb a little before replacing parts. Then you let it sit and it evaporates. You can pick up a cheap tach off Amazon if it's difficult doing it by ear. You can also check the plug. Could be other things but that's an easy place to start.

 

[tstex]

Thanks again for the feedback guys...I've been under the weather and plan on going out in the next few days and will post back what I find...thanks again and HNYr !!