Barn Find Stihl 031 AV

[Cliff R]

I'm not sure I was setting the points correctly but got good steady fire at .010". Put it all back together and it fired right up, and I ran an entire tank thru it.

Bad news, refilled it for another go round and it woln't even pop! Not quite sure what's going on but for sure it's time to convert this one to electronic, if the parts exist to do so. Anyone have a link to the correct module/conversion?.....

 

[Brushwacker]

The points weren't far out of adjustment so I fear other issues. I cleaned them up a bit and set to .016".

Spinning the engine with my drill it's firing nicely once moving pretty fast, but inconsistent at very low speeds and often not firing at all. Not sure what's up with that?........

I'm not sure I was setting the points correctly but got good steady fire at .010". Put it all back together and it fired right up, and I ran an entire tank thru it.

Bad news, refilled it for another go round and it woln't even pop! Not quite sure what's going on but for sure it's time to convert this one to electronic, if the parts exist to do so. Anyone have a link to the correct module/conversion?.....

Sounds like either the coil or condenser likely could be the issue. Those older saws like that have been tricky for me also with ignition problems. Suggest you try the easiest and most inexpensive fixes first.

 

[Cliff R]

I'm going to walk away from it for a few days, I'm so good at stripping this thing down I'm under 3 minutes to get it all the way down to where I can access the flywheel. I'm going to pull the flywheel next time I work on it, and do a little research to see what's available for ignition components.....

 

[HarleyT]

I'm going to walk away from it for a few days, I'm so good at stripping this thing down I'm under 3 minutes to get it all the way down to where I can access the flywheel. I'm going to pull the flywheel next time I work on it, and do a little research to see what's available for ignition components.....

I'll look tomorrow, I likely have a good module. I have a lot of 011 carcasses.

 

[Jed1124]

Sound over simple but….new plug? I’ve had old plugs play games where I thought it was fuel because I had spark but that spark was not maintained under compression or at running speed.

 

[Cliff R]

The first thing I did was to replace the spark plug, have been bitten pretty hard in the past by bad plugs causing all sorts of running issues. I don't know at this moment whether it's a fuel or ignition issue. It ran thru an entire tank of fuel without any problems, then stalled out when the tank went empty. I re-filled the tank expecting to go right back out and finish the tree I was working on, and it woln't even pop.........

 

[Cliff R]

Got it!
I walked away from it and came back with a fresh attitude and started troubleshooting all over again. To my surprise the saw had great spark so the cleaning and point gapping must have been the issue there.

It didn't even try to "pop" so I removed the carb and the bowl was empty. Vacuum tested the fuel lines and even removed the tank line and filter and cleaned it again. Had the carb off 4 or 5 times and each time it would NOT refill the bowl.

The saw would run if I put an eyedropper of fuel into the intake before installing the carb, then die and and NOTHING.

I even put the old needle back in it, nothing. On try # 4 I "munched" the spring so had to steal one from another carb. Got lucky and found one that was really close in length, wire diameter and number of coils. Still nothing....WTF?

Then I noticed that the screen looked a little dark so I took a closer look and low and behold it was plugged SOLID! I had replaced it during the carb build and had lightly blown thru that passage in both directions but the debris was packed in there and "mushy" so it stayed put. Had to remove the screen, clean it out, then put the carb back in place and it roared to life it two pulls.

Not sure how it got there as I had cleaned out the filter, flushed the tank, etc. I even made a new inner filter out of a small sliver of cotton tee shirt I rolled up. I suspect the "mush" was from the original filter core as mentioned above and must have been lodged inside the stock fuel lines. The fresh fuel cut it loose and flushed it into the carb when I ran the first tank thru it.

Anyhow, power is restored and I cut my first load of wood with the 031. Pretty decent power and never grumbled once even cross-cutting some huge pieces of hard Ash that had fallen recently.........Cliff

 

[HarleyT]

Yeah, I always tell folks to remove that screen, as well as the needle/lever/spring and hold it up to a light. If it is halfway plugged up, or all the way plugged, you can tell easily.

 

[Bob Hedgecutter]

Got it!
I walked away from it and came back with a fresh attitude and started troubleshooting all over again. To my surprise the saw had great spark so the cleaning and point gapping must have been the issue there.

It didn't even try to "pop" so I removed the carb and the bowl was empty. Vacuum tested the fuel lines and even removed the tank line and filter and cleaned it again. Had the carb off 4 or 5 times and each time it would NOT refill the bowl.

The saw would run if I put an eyedropper of fuel into the intake before installing the carb, then die and and NOTHING.

I even put the old needle back in it, nothing. On try # 4 I "munched" the spring so had to steal one from another carb. Got lucky and found one that was really close in length, wire diameter and number of coils. Still nothing....WTF?

Then I noticed that the screen looked a little dark so I took a closer look and low and behold it was plugged SOLID! I had replaced it during the carb build and had lightly blown thru that passage in both directions but the debris was packed in there and "mushy" so it stayed put. Had to remove the screen, clean it out, then put the carb back in place and it roared to life it two pulls.

Not sure how it got there as I had cleaned out the filter, flushed the tank, etc. I even made a new inner filter out of a small sliver of cotton tee shirt I rolled up. I suspect the "mush" was from the original filter core as mentioned above and must have been lodged inside the stock fuel lines. The fresh fuel cut it loose and flushed it into the carb when I ran the first tank thru it.

Anyhow, power is restored and I cut my first load of wood with the 031. Pretty decent power and never grumbled once even cross-cutting some huge pieces of hard Ash that had fallen recently.........Cliff
View attachment 930323View attachment 930324View attachment 930325

Excellent work, you didn't let the old girl beat you and solved the problems you were having.
I would still be keeping my nose to the ground for an 011 module to have for when the old ignition fades away, but in the meanwhile- your health to enjoy.

 

[Cliff R]

"Yeah, I always tell folks to remove that screen, as well as the needle/lever/spring and hold it up to a light. If it is halfway plugged up, or all the way plugged, you can tell easily."

Good plan. It never dawned on me that it would be plugged up from one tank of fuel. I'm using 10 percent ethanol so whatever "varnish" was in the tank and lines that didn't get removed from the first clean-up went right into the carb. Most of it would have had to been in the lines. In any case a mistake I woln't make again.

I did notice that this new fuel was swelling up the 40 something year old fuel line a bit, and it was getting pretty "soft". I'll put a new one on order and get a new filter as well.

If nothing else I'm now a expert in taking one of these apart and putting it back together. Very simple design compared to some of the newer stuff I get involved with.......

 

[HarleyT]

Yeah, the partly clogged passage can act real squirrelly. It can run pretty good until put under a load and then start to lean it out. Also those soft fuel lines can kink and collapse, giving intermittent problems too. I guess the newer fuels soften them up, plus old age.

 

[Cliff R]

It appears all of the replacement fuel lines are "off-shore". Hopefully they will hold up in this new fuel.........

 

[Cliff R]

One observation and a question. The rubber AV mounts are in good shape, but the saw still seems to have quite a bit of movement between the main components. The upper mount is held in place by a long screw with a shoulder in the middle of it. Not sure exactly what it up with that deal and couldn't find any other parts listed in the IPL so it doesn't appear I'm missing anything. Seems like it has a lot of "play" in that area, just wondering if that is normal for one of these saws?.........

 

[HarleyT]

Sometimes they look OK on the saw, but are ripped/separated where they join the metal plate.

 

[saxman]

I’ve changed a few down through the years. If you plan on really using the saw I would change them while your going over the saw. If I remember correctly those old horizontal cylinder saws aren’t the easiest to work on


Sent from my iPhone using Tapatalk

 

[HarleyT]

Well, it is a laid back cylinder......
It really isn't that hard to work on, unless someone before you has messed up the cheesehead screws.
Which is usually the case.

 

[Cliff R]

Turns out the top mount as shown in the pic above has separated. Looking for a complete set to order, figured I'd just change all of them while I'm at it......

 

[HarleyT]

Looks like the aftermarket crowd has started cranking them out.

I wonder how they hold up.

 

[Cliff R]

The upper mount finally showed up and low and behold it's not the correct part. The bolt spacing was too wide, so they must have made several variety on that series of saw. Not a big deal, a few minutes with a chainsaw file to "slot" the holes and it's in place and working fine. I also picked up a module for it to replace the points but going to save that modification till it acts up again. I've put three tanks thru it so far and it's running fantastic with no issues anyplace.......