Need a little 031 Stihl insight/tips

Went over to help an old family friend get down a bunch of larger dead ash around his home. He's over 80 years old and still saws!

He has several 031 Stihls. His best one scored out so he was trying to get another one going when I got there. Here is what I know. He bought a new carb kit and installed. Started VERY hard and when it finally did run it was at a faster idle. Adjusting low and high did nothing but kill it eventually. When you pull the throttle speed does not change but sound does, like the pitch goes lower and loses even more power. we ended up just using mine as it was a half day of cabling them down as they were pretty bad leaners. He has several 031 Stihls and I want to go over and help him get them back in order, at least one anyway His best one scored out so he was trying to get another one going when I got there.

I'm taking compression gauge, new solid state coil to get rid of points and such and will look it over close. Any suggestions for anything else? I've worked on an 028 but these are a little older. All of them are AV's but no chain brakes.

One odd thing was he said he bought a carb rebuild kit earlier(from Stihl dealer) and it ran fine for about an hour then quit. He said when he took the carb back apart the diaphragms were all curled up. Ever heard of that? He was blaming alcohol and got av gas after that. I've never had it effect something that quick.

Any tip or suggestions appreciated.

 

i'd be checking the intake boot and the impulse hose for damage.........i think i still have a good used boot if you need one or there's always the bay....

 

the saw dont start easy because of low compression, leaks , bad coil
For the full throtle if you mean that the sound change and the chain speed dont, take a look to the clutch, sprocket

 

Okay, Just got back and did some checking on stuff. He has 4 complete 031 av's pre chain break models. First we checked compression on all of them. 140, 155, 160 and 175. I do not have a vacuum check tool, I guess I should get one. Any reasonable sources for one? We chose the saw with the best compression which was the same saw we tried to start before. When we tore it down I looked over the boot and impulse line but just a quick visual. It was before I saw that some here say that is a common issue.

We just wanted to try the solid state coil so we pulled the flywheel as I didn't want to just clip the wires and have that to deal with if it was not the problem. Egg on my face as when we went to put the new one on it would not line up with the mount holes, even though it was said to fit saws up to a 044. I bought 5 of these coils when I did my 028 WB and it has worked flawless for several years now. I told him I'd search tonight to try to find a coil that would bolt on right.

He also told me he had a 009L Stihl that would not run. I have 3 009's and know those like the back of my hand. I had coils for those so I tore it down and installed it and in 45 minutes he has one saw that runs perfect now. I guess all was not lost.

I will look at the impulse line and boot close when I go back as he has plenty of parts there to swap. I've had so many bad experiences with Stihl coils and points I shy away from trying to make them work. I was ready to toss a few saws as the spark snapped the gap strong and thought that was not the problem. Rebuilt carbs, thought timing somehow was off and when I switch to a solid state coil, it ran fine. Even saws dealers said were junk.

I let you know what I find and if anyone knows of a coil source, I'm off to the net and ebay to find what I can. Thanks for the input.

 

use compresed air and soapy water for find the leaks if you see bubbles you have leaks no need pump

 

Pushing the throttle made no increase in RPM, actually lowered it some. Clutch, chain and sprocket are fine with no drag.

 

Appreciate the tip

 

thank you sir

 

so now test the coil , the fuel tank vent , and if in the carb is everything assembley corect

 

Looks like I'm forced to deal with the stock coil as this saw is an oddball. See on Ebay there is a guy who will convert owners stock coil for $95.00 so that is out and can't find any premade ones in a decent price range. I'll report back what we get and thanks again for the input.

 

maybe this help a little

 

You sir are my hero. We'll test the coils we have to eliminate that and maybe order the universal ignition part they suggest. Someone had converted that 009 with one of those so maybe we'll try that out too. Looking better thanks to you.

 

i just try to help

 

I had several of these at one time too. I converted the ignition over in two of them. One used the electronic flywheel with a universal type module. It ran OK, but not kick as strong.

For the second one I sent the coil and flywheel out to the guy in California when it only cost about $60 a couple of years back. He exchanges your flywheel for an electronic one and "operates" on your coil sealing it back up with epoxy when finished. I think the idea is that you remove/reduce the advance that is built into the coil and instead get it from the new flywheels keyed advance? However that is, that saw ran very strong. Besides the ignition issue, leaky gas tanks and no safety features are the downside to those old gems.

 

I have an 031AVE carcass with a known good solid state coil I'll give you if you need it.

 

Lukem's offer is gold! Assuming he has the flywheel too. When I get a non-electronic 031 with any sort of ignition troubles I swap it out for an electronic (need both the coil and flywheel) ignition. Unless it's an attempt to avoid spending any money at all I don't mess with the points setup.

In my experience the carburetors (virtually all variations) on the 031 are problematic too. Don't rule that out . . . I've seen that model do some very strange things that a carb swap completed eliminated.

 

Flywheel is there. I'll get some pics later.