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Adjusting points on a Stihl 031 AV (needed a 3 lb sledge to get the crank out)

Post in 'The Gear' started by Boog, Nov 4, 2012.

  1. Boog

    Boog Minister of Fire

    Joined:
    Oct 31, 2012
    Messages:
    592
    Loc:
    NE Ohio
    Ok, first please bear in mind that I never worked on any small chainsaw engines before this month when I apparently successfully rebuilt my Stihl 191T which had a broken connecting rod (previously posted). That "knock-on-wood" success encouraged me to tackle my real prized possession ....... an 031AV that my 2nd ex-wife (have three of those) gave me for christmas back in 1980. It was my only saw for about 20 years, and then still gave me another 10 years of moderate use once I picked up smaller and bigger ones to help it out. It literally ran great for almost 30 years before it guickly started loosing power, running eratic, smoking excessively, and finally quit to nothing more than a gasping cough. I gave it up as shot and put it aside to eventually part out or sell complete on ebay.

    I decided to have a go at it though and first bought a carb kit. I started it up after the carb rebuild and to my amazement it actually started running real good. But over the next 2 minutes as I tried to adjust the carb it quickly got worse, started smoking alot and wanted to quit. I could barely keep it running regardless of carb adjustment so I shut it down. I'm assuming that at this point the carb was good and I had other internal problems, probably worn piston, rings, cylinder, etc. and it was overheating and quitting. So I gathered up the modest tools I had and had at it. It took me the better part of the day to get it totally appart. It was easy up to the final step of separating the case to get the crank out. That sucker would just not come appart. I did not want to pry around the seam as to damage the gasket surfaces so I figured you just had to support one side of the case and drive out the crank to the other side. Easier said than done, that crank just did not want to separate from the bearings and let go. I was using blocks of wood to support the one side of the case with separation room underneath, pounding on the end of the crankshaft with a 20 oz hammer and block of hardwood. After pounding on this many times as hard as I dared the best I could do was just open up a crack in the seam around the case.

    I was about to give up on it and just go ahead and part it out when my teenage daughter finally came down in the basement to see what all the noise was. She suggested I just get a bigger hammer! So I grabbed a 3 lb hand sledge and let it fly. Hard the 1st time, really hard the 2d & 3rd time, and presto, on the 4th slam it separated about a 1/4". I gave it one more big hit and she split in two.

    My bottom line question is this. After I install a new piston/rings assembly and maybe a used/new cylinder, new bearings/seals, (crank actually seems really good) how do I go about adjusting the points. I can't figure how one would measure the gap with the flyweel out so you can get at them. I see the "hump" on the hub of the flywheel that opens the points, and they look pretty good, and the saw ran nice when first started up with the rebuilt carb, but I'd like to check it now.

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  2. MasterMech

    MasterMech Guest

    If you're serious about using the saw day in and day out, I'd look at eliminating the points either via an aftermarket transistor module or obtaining the factory electronic ignition module. Aftermarket solution is cheap and easy but I get it if you want to keep the old girl all original.

    My 031 has not needed any ignition work yet so unfortunately, points adjustment is not something fresh in my mind. I'm sure Hearth.com Members (PM him if he doesn't chime in here soon) can help since he loves these old tanks.
  3. Boog

    Boog Minister of Fire

    Joined:
    Oct 31, 2012
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    592
    Loc:
    NE Ohio
    Thanks MasterMech, never thought about switching out the points to electronic ignition, but it does seeem like a logical way to go at this point. I searched around the net a little this morning and found a few references to available products. Also found these two very helpful videos produced by "LIL RED BARN POWER EQUIPMENT SUPPLY" that show just how easy it is to do this on an 028.





    I'm going to call them later today, they don't open up till after 5pm on Mondays.
    MasterMech likes this.
  4. MasterMech

    MasterMech Guest

    Ran the snot outta my 031 today. Gettin' to see why they were so popular. :cool:
  5. Boog

    Boog Minister of Fire

    Joined:
    Oct 31, 2012
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    592
    Loc:
    NE Ohio
    I know MasterMech, like I said, mine ran like a charm for almost 30 years, nice power to weight ratio I thought. I ended up doing the following with mine: After evaluating the cost for new bearings, seals, case gasket, and crank (turned out the wrist pin bearing hole on the top of the crank was worn) I ordered an entire complete used case and crank assembly from Cheap Chain Saw Parts. That had about 15 of them there and were not busy so the guy looked over several that I had ID on ebay and picked out what appeared to be the nicest tightest unit. It was incredibly clean looking on the ebay pic compared to most others and he said the crank was really nice and smooth, all for $25. Then he picked me out the nicest looking used cylinder (bore condition) and piston set, again from about a dozen showing on ebay (ebay pics don't show bore condition), that was $30. $10 for new rings, $3 for new oil pump gasket, $5 for new impulse line (pinched a hole in mine working on it), new head gasket for $6. Then I really splurged to dress her up and bought a really mint complete top/handle assembly for $20. Mine had a big chunk broke off the front corner over the cylinder fins (had something big fall on it many years ago) and my black rubber piece on the grip was cracked in two spots. Could have skipped that but what the hell .... she's going to look pretty now too. Also picked up a long T-handle Stihl 4mm driver for the cylinder bolts (disassembled it with an L shaped allen wrench that was SAE, a little loose, and barely long enough) for $7.50, and lastly the proper piston stop tool for $9.50 so I won't need to do the old "rope stuffed in the cylinder trick" to assemble/disassemble saws in the future. The total with the tools came to $116 and they only charged me $24 to ship it all from WA. Maybe could have saved a tad on an item here or there at another place but by combining the shipping I saved a lot.

    Also talked to the folks at the LIL RED BARN in regards to the 028 electronics referenced above ..... it will not fit the 031 AV, guess I'll stick with my points ignition system too unless I can find another electronic one that will work.

    NOTE: 10 pm 11/5 - I just figured how to adjust the points. I was cleaning up the flywheel and noticed the two plastic inserts screwed on the top. Sure enough, when you remove them it exposes the locations where the point adjustment screws are located! Didn't realize the significance of those little plastic inserts. Learning more each day that I fool with this puppy.
    MasterMech likes this.
  6. MasterMech

    MasterMech Guest

    Mine needed a new carb box and air-filter cover. Somewhere along the line it lost a chain and the chain took out the carb box. It was missing the clutch cover and every AV buffer on it was shot. The carb was assembled incorrectly, actually, someone omitted a diaphragm and that allowed it to suck fuel straight from the tank through the impulse line and into the crankcase. There were lot's of little things too, like impulse and fuel ines, gaskets... No porblems with the actual engine on mine, ran well once the carb issues were corrected. I did some work on the recoil starter, threw a rim sprocket kit on it, and a new 16" bar & chain. (3/8" .050, 33RSC-60)

    The baffle in the muffler is loose, can't seem to get it to line up so I can run a screw in it either. It's outta the way and not creating issues so I'll just call it a "muffler mod" (hey, that counts, right? ;lol ) and I'm getting to like the extra growl she's got now anyways. ::-)

    Saw is surprisingly smooth for something that was built 35 years ago. I've got more $$ than you tied up in mine (hence it's the "Charity Case") and if I were to sell it, I'd be lucky to break even. But that's not why I brought her back to life. ;)

    Mine runs on the original points but maybe if you still have trouble with yours, you could look into doing a Mega-Fire or Nova module?
  7. Boog

    Boog Minister of Fire

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    Went ahead and ordered the Mega-Fire module, it was only $14. Once I get it all put back together with all the other parts I bought, I'll test is out with the old points and condenser first. If it runs good at least I'll know those parts are fine to either keep for the future (in case the module doesn't seem to run right or acts up down the road) or sell them on ebay. I might have found part of my problem cleaning parts up last night, the contact face on the coil was just totally loaded up with 30 years of gunk on it. It had to have filled the entire .010 - .012" or so of gap between the flywheel with packed in crud. It must have taken me a half hour to carefully clean all the crap off that coil/wires. I never had that side of the saw appart before to realize how dirty it had gotten under there. Always kept it clean on the other side around the carb, but not under the cover at the coil.
  8. greg13

    greg13 Feeling the Heat

    Joined:
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    CNY
    The 031's were as close to a bullet proof saw ever made by anyone. We ran lots of them when I worked for the tree company. I used to have boxes of used parts (usually from when the parachute failed to deploy from 40') that I wish I had now! There were about 2 ways to kill them, either a 40' fall or "I could swear I added oil to the mix".
  9. Boog

    Boog Minister of Fire

    Joined:
    Oct 31, 2012
    Messages:
    592
    Loc:
    NE Ohio
    Well, I finished my 031AV rebuild tonight. Going to fire it up tomorrow morning and see how it does. Overall, I put the following items into my old 1980 saw:

    1. Complete used case and crank assembly (versus a crank, bearings, seals, case gasket bought seperatly)
    2. Used cylinder and piston, new gasket, new rings, new needle bearing, 1-jury-rigged circular retaining clip made by cutting a piece of an appropriately sized stainless steel spring >>
    3. Walbro carb rebuild kit, new fuel line, new impulse line.
    4. New oil pump gasket
    5. Going with the old points and condensor for now although I bought a new Maga-fire electronic module to put in down the road. New crank/flywheel key.
    6. New chain catcher.
    7. Free used Gas cap thrown in
    Total with shipping $134

    8. Then I splurged and bought a complete mint used top handle assembly to really dress her up. (mine had a chunk broke out of it over the front corner and cracks in the black rubber part of the grip) Didn't "need" this to make her run, but splurged for looks! Another $20.

    More money could have bought me an alleged "good runner" 031AV on ebay, but you never know the history/what your going to get. There is one on the Youngstown CL just today going for $275. I know exactly what I have in this. Plus, now I have some used parts of my own to peddle off on ebay and recover a little of my cost!

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