STIHL 031 AV advice

[sled_22]

I have an 031 AV electronic. Well technically I have 3 of them but I bought them as a non running lot for hardly anything. I have cleaned and fixed up the best looking one. I replaced the intake boot, fuel lines/filter, carb kit, spark plug etc.
I have 145-150 psi compression cold. I have a wet plug when pulling it over. I have witnessed spark via my inline test light. carb is 1 turn Low and 1 1/4 high. meter valve set correct. swapped ignition modules, swapped coils, checked the muffler for blockage, fresh fuel, swapped fuel caps and check for blockage, flywheel key in place and not sheared, contacts for coil and flywheel clean... etc. I still can not get this saw to fire. The only thing I haven't done is vacuum test but i don't have a tester. I have never had a problem with a saw at least not firing to need that.
Does anyone have any other ideas as to something i can look for or check?
(also, am i the only one that thinks the recoils on these 031s are a POS?)
Thanks to anyone that can reply.

 

[hotshot]

If you can, post a couple of close-up pictures of your current coil, module, & flywheel.

The FW may be for the older points version & not for the correct electronic type. Timing may be retarded.

You have visible spark, fuel & great compression, so it should at least burp or fire off during starting. Assume that the plug is correctly gapped at 1/2mm...

 

[arto_wa]

Flywheels mixed up hmm...?
Interesting - watching

 

[sled_22]

Alright. I have the 032 part number one is in the saw right now that matches the second set of pictures
. The one with the broke fins is the one that came out of the saw. I also have a 043 part number that came off one of the saws.

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[sled_22]

I should note the flywheel I used matches exactly the one with broken fins that came off from the saw. Maybe the wrong flywheel was installed???


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[hotshot]

The first FW pic is correct, you need to look for the transistor symbol cast on the FW.

Some electronic FWs have the point adjuster ports, & that’s one.

The third one may be electronic but it’s too grime covered to tell.

 

[sled_22]

What's the "tell" between an electronic and non electronic flywheel?
Is there any IPLs for these?

 

[hotshot]

Good morning. As stated, the little cast in symbol of a transistor is one way to “tell”, but the keyway slots are positioned different between the two & usually no point adjuster windows are included on the electronic version.

There’s likely another issue, as it will usually start with a points FW, just not run right.

Google ‘Stihl 031 IPL’ or go to the ‘Beg for manuals’ sticky thread here on AS to ask for one, plus Mr. Ray Benson might also have a copy of the 031 service manual.

 

[sled_22]

You said right there I'm looking for the transistor symbol..... urgh Sorry i didn't see that. I saw "first picture is correct" and immediately scrolled back up to look at it.
I don't know when i'll get a few minutes to take the tank back off and check the numbers on the coil or ignition. Friday night is the most likely scenario.
Thanks for the information. I'll check back once I get the correct FW in and reevaluate.

 

[sled_22]

@hotshot you also mentioned the spark plug gap. Looks like .020. THis could be a problem too. There's a gap in all the spark plugs i removed from these says that you can stick a screwdriver point in. .020 is hardly anything. I bet i'm not getting spark in the combustion chamber even though i'm seeing spark in the spark tester. I wouldn't be surprised if all those plugs are gapped out to 1/8". (.125) (3.175mm)

 

[hotshot]

With the old points & a good condenser (OEMs failed a lot), those 031 saws threw lightning bolts.

The later new electronics gave a thin stingy blue spark, so plug gap is critical.

The AS info search is broken, as there are a lot of 031 flywheel threads from old member Lakeside53 that can’t be found because “031” is now too short to search.

Not sure WTF the AS website was thinking when they truncated the search. You can back out & go through google to find them though...

Good luck with the saw!

 

[sled_22]

Well I switched the flywheel tonight. Had spark in the tester. Gapped the plug to .020. It was about .028.
Pulled about 15 times and no fire. I have fuel pushing back out the carb now though. Maybe I missed something in the carb on the rebuild? Plug is soaked though after pulling so idk.....

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[sled_22]

The flywheel I have pictured above is the one I removed btw. I did install one with the stator symbol.


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[cscltd]

Your carb may be flooding so much that so much fuel is in cyl it can’t burn it. Pinch/block fuel supply and see if you can get it to fire after saw clears out some fuel? Also on points units closing plug gap to 10 thou or less will Sometimes run and thus tell you that ignition is breaking down and can’t fire under compression

 

[KASH]

Sled 22 sorry I can not be of any help but maybe you can help me. I need a picture of the flywheel key even if it is with the key still in the crank.I had the key shear on my 032 and the key is NLA a poster gave me a number for the key I ordered two and I can not get the key to fit.
Thanks Kash

 

[sled_22]

Yeah I'll take a picture and get you some dimensions tonight assuming it's the same between the 032 and 031. I do have an 032 under the bench that's next in line so if I get some extra time I'll pull that flywheel and make sure they match.
Regards,
Sled

 

[hotshot]

Sled 22 sorry I can not be of any help but maybe you can help me. I need a picture of the flywheel key even if it is with the key still in the crank.I had the key shear on my 032 and the key is NLA a poster gave me a number for the key I ordered two and I can not get the key to fit.
Thanks Kash

That’s just a common metric woodruff key 2x3.7mm, a hardware store item, or $10 for 25 of them from McMaster-Carr.

https://www.mcmaster.com/98490A130