New (to me) chainsaw: 1977 STIHL 031 AV

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Wright Saw

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So, I got a couple new chainsaws recently. Was working on them for a customer but ended up getting to keep them because of how much the repairs would cost.
One is a new-ish (2013) plastic Homelite 3816 C chainsaw, with carry case. It idles, but won't rev up, even after replacing fuel lines/filter/primer bulb. Gaskets/diaphragms looked fine, so I'm thinking a check valve or welch plug went bad/is leaking, so it needs a new carburetor.

And the other is my first Stihl. It's an 031 AV, with a serial number, made in West Germany. Every part I can see on it (except for the Oregon chain) is genuine Stihl, so when replacing most parts I'll only use Stihl. From several (77) cast date wheels on various parts, I'm assuming it's a 1977. It has anti-vibration, throttle lockout, and a hand guard, but no chain brake or heated handles.
Before I got it running, I checked the compression, and I remember it had around 160 psi. I rebuilt the carburetor, installed new genuine Stihl fuel lines, filter, AV buffer, impulse hose, cleaned the fuel tank, freed up throttle trigger, and cleaned the mesh air filter. It does not say electronic on the tag and there is no "K" symbol on the flywheel to indicate electronic ignition, so I would guess it has points. But, it's always had good spark, and I've never pulled the flywheel. So, that leads me to believe it may have electronic ignition.
I started it once (took many pulls since it had been sitting so long) and it ran good. Idled and revved up fine. While idling, the saw stalled out. I looked later and saw that one of the clutch linings came off the shoe and wedged itself between another lining and the drum, causing the clutch to stay engaged to the sprocket. The saw probably stalled out because of the load at idle, and I haven't attempted to start it since. I'm going to try some new shoes instead of replacing the whole clutch. It also needs a bar, chain, sprocket, and some other little things to get it fully functional.
Coincidentally, it takes 3/8" pitch x .050" gauge chain with a 16" bar, same as my Homelite SXLAO and Husqvarna 36, so chains should be interchangeable between the three of them. The bars, however, are not. My new plastic Homelite also looks to have 3/8" pitch chain and a 16" bar.

I will post pictures soon, and update this thread with progress I make on fixing this saw. Thanks for reading
 
Good luck with your project. Sounds like a fun one! I have two of these 031's I plan to rework, but not soon. I am at an age where I am approaching retirement. So I am amassing a pile of good rebuild candidates to work on when I call it quits on the day job! Who knows....I may actually open up real business some day!
 
Good luck with your project. Sounds like a fun one! I have two of these 031's I plan to rework, but not soon. I am at an age where I am approaching retirement. So I am amassing a pile of good rebuild candidates to work on when I call it quits on the day job! Who knows....I may actually open up real business some day!
Thank you. Good luck with your projects, too.
 
Here are some pictures:
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Overall, it's in pretty good condition for the age. Looks like it wasn't used a whole lot. Handlebar wrap needs repair.
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The logo. Probably my favorite of all chainsaw logos. I'll try to get a better picture, this one is kind of blurry.
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The air filter cover was missing when I got it, but I bought a good OEM used one on eBay.
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The bar nut/stud threads were messed up, but I restored them to 8 x 1.25 mm with a tap and die. Bucking/felling spike is nice and sharp.
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DSCF6501.JPG
I like this muffler design. Also, looks like the spark arrestor was removed at some point.
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Bar is an OEM Stihl 16" hardnose, perhaps the original one. Rails are worn out. Chain is Oregon.
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Saw also came with this short bar cover.
 
One of the first saws I started with, early '80s...great saw! you should be able to find the chain brake parts...looks like you're just missing a few things.
Thanks.
Yes, it is missing just about everything for the chain brake. I don't think this saw was factory equipped with a brake, just a hand guard. I looked into it some, and I think for the brake to work I would need a brake equipped clutch cover, an isolater clutch, and a different hand guard. Maybe one day I'll get the parts to do it.
 
The chain brake was on option in the old days... The first series 031 AV had a white (colorless plastic) handguard.
This saw seems to be equipped with points. On the points model the flywheel has two windows which are plugged (plastic covers with a screw in the center, if I remember correctly). After removing the screw the cover can be pried out to gain access to the points for adjustment. No need to pull the flywheel...
 
It almost looks like that cover isn't original to the saw. The one that was passed down to me was bought by my stepfather in the late '70s...had the brake.
the guard has the slot that the brake rod rides in.
It's entirely possible the cover was replaced at some point in time. I think the cover on it now has a (77) date wheel, so it's at least period correct. I did notice the slot for the brake rod in the hand guard, but I thought the guard on brake equipped saws pivoted forward more.
 
It's entirely possible the cover was replaced at some point in time. I think the cover on it now has a (77) date wheel, so it's at least period correct. I did notice the slot for the brake rod in the hand guard, but I thought the guard on brake equipped saws pivoted forward more.
That was going to my next Q :p
How far does it pivot? The one I had went nearly horizontal when engaged.
 
The chain brake was on option in the old days... The first series 031 AV had a white (colorless plastic) handguard.
This saw seems to be equipped with points. On the points model the flywheel has two windows which are plugged (plastic covers with a screw in the center, if I remember correctly). After removing the screw the cover can be pried out to gain access to the points for adjustment. No need to pull the flywheel...
Thanks for the information. This saw does have two white plastic plugs in the flywheel, with a screw in the middle of each one. I didn't know the points could be accessed through them, without removing the flywheel. That's a very clever design. Thanks for telling me.
 
That was going to my next Q :p
How far does it pivot? The one I had went nearly horizontal when engaged.
The guard seems to rest about at the angle shown in my photos, not exactly vertical but not very close to horizontal either. A pair of lugs made into the guard seem to stop any further forward movement. It moves freely backward, all the way to the handlebar, and a spring pushes it back until the lugs rest on the top cover as in the pictures. But I've never really pushed forward on the guard to see if it would go further, for fear of breaking those plastic lugs.
 
The guard seems to rest about at the angle shown in my photos, not exactly vertical but not very close to horizontal either. A pair of lugs made into the guard seem to stop any further forward movement. It moves freely backward, all the way to the handlebar, and a spring pushes it back until the lugs rest on the top cover as in the pictures. But I've never really pushed forward on the guard to see if it would go further, for fear of breaking those plastic lugs.
Ah, interesting. The guard looks the same but isn’t, I guess
The older fixed guards that I’ve seen are white with no spring as described by another.

There are a couple on eBay. One looks like yours and the other has the same cover as mine but is missing the rod
 
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