Stihl 031 AV

[dmezzomo]

I am working on a Stihl 031 AV. One day it runs perfectly and the next day no spark. I turn it over with a 1/2” drill and I get spark again. Then replace recoil and starts with recoil and runs perfectly.
Next day, no spark. This thing is driving me nuts.
It has an electronic coil with a trigger under the flywheel. Any ideas please??

 

[RED-85-Z51]

I am working on a Stihl 031 AV. One day it runs perfectly and the next day no spark. I turn it over with a 1/2” drill and I get spark again. Then replace recoil and starts with recoil and runs perfectly.
Next day, no spark. This thing is driving me nuts.
It has an electronic coil with a trigger under the flywheel. Any ideas please??

Mine was a points model and had no to very little spark at lower speeds. I put on a solid state module and my spark problems went away. Is yours the type with the external coil and points under the flywheel?

Sent from my SM-G996U using Tapatalk

 

[HarleyT]

You know this for a fact?

It has an electronic coil with a trigger under the flywheel. Any ideas please??

 

[dmezzomo]

You know this for a fact?

Yes. Had the flywheel off twice.

 

[dmezzomo]

Mine was a points model and had no to very little spark at lower speeds. I put on a solid state module and my spark problems went away. Is yours the type with the external coil and points under the flywheel?

Sent from my SM-G996U using Tapatalk

It has a trigger under the flywheel.

 

[RED-85-Z51]

It has a trigger under the flywheel.

Was it blue?

Sent from my SM-G996U using Tapatalk

 

[dmezzomo]

Was it blue?

Sent from my SM-G996U using Tapatalk

Black . I found a parts diagram for this saw and the earlier models had points and condenser, the next model had a coil and a trigger like mine and the latest models had just an electronic coil.
The coil is obsolete and they cannot be found anywhere.

 

[HarleyT]

I never could find enough room under there for a ignition chip. Could be grounding out in there. Stihl put theirs up on a bolt of the coil. You might double check the wire and module for rubbing, and snap a pic of it while you are in there.

 

[HarleyT]

I never came across this one here, so I cannot say much about it. But in general, the coil is usually fine, and the fault is in the trigger or grounding out somewhere.
https://store.chainsawr.com/products/stihl-031-av-chainsaw-early-electronic-ignition-coil-kit

 

[dmezzomo]

I never could find enough room under there for a ignition chip. Could be grounding out in there. Stihl put theirs up on a bolt of the coil. You might double check the wire and module for rubbing, and snap a pic of it while you are in there.

This trigger is half round and fastened with 2 screws. I removed it to check for bare spots or possible grounding but everything appears fine. I had it running this afternoon and it ran great but I will see what tomorrow brings. The kill switch is broken so I got 3 jolts from the coil that nearly knocked me on my a$$!

 

[HarleyT]

That switch may be your problem.

 

[cookies]

I had a plug wire pull that bullchit on me for a week, I changed the orientation of the metal clip on the plug end and cut 3/16 off the coil end and it ran like a champ

 

[dmezzomo]

I had a plug wire pull that bullchit on me for a week, I changed the orientation of the metal clip on the plug end and cut 3/16 off the coil end and it ran like a champ

If I keep having problems, I will try that. Thanks

 

[dmezzomo]

That switch may be your problem.

I willing check this out in more detail. Thanks

 

[dmezzomo]

I have tried everything with this saw. It will have spark 5 days in a row and then … nothing. Next day or so it will have spark again. When it has no spark, I take the recoil off and spin the motor really fast with a 1/2” drill and it always starts then I have spark again. Could it be that the trigger loses its charge and then turning it over really fast re- energizes the trigger? The trigger appears to have some kind of a small resistor or something pressed into it. About 3/8” in diameter. I have been playing with this saw for about 3 months now. It runs perfect when I have spark.

 

[a. palmer jr.]

Is it possible that the kill switch wire is grounding to the saw when the recoil is on and becoming ungrounded when you take the recoil off? Many of the older Stihls had a problem of the kill switch wire shorting out...

 

[HarleyT]

I have tried everything with this saw. It will have spark 5 days in a row and then … nothing. Next day or so it will have spark again. When it has no spark, I take the recoil off and spin the motor really fast with a 1/2” drill and it always starts then I have spark again. Could it be that the trigger loses its charge and then turning it over really fast re- energizes the trigger? The trigger appears to have some kind of a small resistor or something pressed into it. About 3/8” in diameter. I have been playing with this saw for about 3 months now. It runs perfect when I have spark.

Sounds like he may have been talking about the condenser. Maybe someone put on a trigger unit and hooked up the condenser.

 

[Ikeholt]

I had a Stihl of that vintage doing about the same thing. Just by chance, I was trying to start it in the dark and could see stray voltage sparking off the plug wire where it routed through the case. So it ran good until there was a little moisture or the wire re-positioned itself, then it would ground itself out. I wrapped the wire good with electrical tape, no problem since.

 

[dmezzomo]

Once I get spark back by turning it over with a drill, I may have spark for a few days. Sometimes I leave it sit in the same place overnight with the plug out and good spark, pull it over in the morning , and nothing!
I have been working on chainsaws for 50 years and never have I encountered anything like this.

I had a Stihl of that vintage doing about the same thing. Just by chance, I was trying to start it in the dark and could see stray voltage sparking off the plug wire where it routed through the case. So it ran good until there was a little moisture or the wire re-positioned itself, then it would ground itself out. I wrapped the wire good with electrical tape, no problem since.

Thank you. It does sound exactly like the same problem as I have actually seem electrical flashes at times from the front of the case where the handle attaches to the case. Also, I have received shocks when my hand was on the case as I was pulling it over with spark plug grounded to the engine as I was checking for spark. Shouldn’t get a shock if plug is grounded.

 

[HarleyT]

Sorry about that last post,, I thought I was commenting on a different 031.

To test on that model for spark, a drill doesn't really turn fast enough, especially on the newer electronic coils. Also testing spark on that model is tricky if you ground the plug on the top cover, as it is isolated from the block a bit from the a/v mounts.