Need help with Stihl 056 ignition fix using Nova II module

[Okie]

Chain trying to run at idle:


You indicate your other 056 does not run the chain at same idle speed as the one your are flogging.

Wonder if you might have a smiggin of a centrifugal clutch issue?(like maybe a weak spring or bearing little gritty or worn)

Might even eventually consider swapping the clutches to see if chain running at low idle issue transfers to other saw!!!!!!!!!!

 

[tntatro]

Chain trying to run at idle:


You indicate your other 056 does not run the chain at same idle speed as the one your are flogging.

Wonder if you might have a smiggin of a centrifugal clutch issue?(like maybe a weak spring or bearing little gritty or worn)

Might even eventually consider swapping the clutches to see if chain running at low idle issue transfers to other saw!!!!!!!!!!

I put new spring on the clutch. I also switched the clutch with a different one before replacing the springs. I didn't switch the bearing though, might have to try that.

I ran the saw today and it started and idled great and had lots of power then after it was nice and warmed up it quit and wouldn't start. After all this messing around the coil maybe done for anyway. Although it would still have spark and not start. I'm confused again. I have learned a little about timing anyway and I think I figured out this fix, just need a good coil to work with. I'm thinking that when I fried the transistor or what ever that other part is called, the coil itself must have also got ruined.

I'll try switching carbs again but I'll likely end up trying my last coil to see if it works. It looks like I got everything I could out of this ignition. The next ignition also had a fried transistor so it may have the same fate as this one. It seems as though when just the capacitor goes the fix works great but in this case I believe the transistor died because replacing the capacitor produced little to no spark. Maybe the transistor and coil both get fried at around the same temperature.

 

[a. palmer jr.]

As far as the chain advancing while the engine is idling, it could just be weak springs in the clutch. I've had several of them and it's hard to get it to idle low enough for it to disengage. A new spring will fix that if that's what it is..
It appears several of us answered this at the same time...

I would check the coil for continuity, it probably didn't go out just because the trigger did.

 

[tntatro]

As far as the chain advancing while the engine is idling, it could just be weak springs in the clutch. I've had several of them and it's hard to get it to idle low enough for it to disengage. A new spring will fix that if that's what it is..
It appears several of us answered this at the same time...

I would check the coil for continuity, it probably didn't go out just because the trigger did.

I did put new OEM springs on. The way it is now with the flywheel and stator plate set where they are it seems to start, run and idle about the same as one of my other 056 saws. I thought it was all good until I used it. It just dies after it gets warmed up and won't start. I have checked for spark right after and it appears to be good and still won't start. If there is spark wouldn't that indicate that there is continuity?

 

[a. palmer jr.]

I did put new OEM springs on. The way it is now with the flywheel and stator plate set where they are it seems to start, run and idle about the same as one of my other 056 saws. I thought it was all good until I used it. It just dies after it gets warmed up and won't start. I have checked for spark right after and it appears to be good and still won't start. If there is spark wouldn't that indicate that there is continuity?

Yes, I believe it does. Possibly a vent problem with your tank? I guess you could loosen the cap to check that. Another possibility is that these older metal saws get hot and that includes the fuel tank..maybe a little vapor lock or something? I know some of my old McCullochs used to boil the fuel on hot days...

 

[tntatro]

It has been pretty hot here lately. I did try loosening the cap. No problems running my other saws. I also tried a different spark plug. I may try a different carburetor and also put on a different style fuel cap and see if anything changes.

 

[tntatro]

I just went out and started it with a different fuel cap and it idled for less than 5 minutes then died. I then advanced the timing a tiny bit and was able to start and run it and it would idle okay. I let it idle for a while and messed with the carburetor settings. If it stalled I could start it right back up.

I guess I'll put it to work again tomorrow and see what happens. It idled better before but I guess it's better to have a slightly higher idle and slight chain advance if it stays running.

I also put a different flywheel on. Same part number. Maybe that was actually the problem.

 

[Okie]

Yes, I believe it does. Possibly a vent problem with your tank? I guess you could loosen the cap to check that. Another possibility is that these older metal saws get hot and that includes the fuel tank..maybe a little vapor lock or something? I know some of my old McCullochs used to boil the fuel on hot days...

My old front mounted metal tank 1-40, 1-50 series of McCullochs also boil the fuel, expecially if it get around 1/4 tank. One guy suggested the bubbles was due to vbibration, not heat, but appears to be heat related, but the saws still run and operate ok.

I think you have two slight problems with your saw, one slight ignition and another maybe carb has slight issue.
Have you swapped in the good carb from your other good running saw?

 

[tntatro]

I'm about to go try it out as is but I haven't switched the carb yet. I did soak the carb in parts cleaner for a few days and then put a rebuild kit in not too long ago but your theories are consistent with what I suspect.

I think ignition problems are the main thing and now I'm wondering about the flywheel but I'll check on that and the carb after I test the saw today. All my carburetors are old but the ones on my two magnums seem to be working good.

If it dies again today I'll be back to thinking the ignition is done for. If it doesn't die then I'll keep fooling with it. Pretty hot out today so overheating wouldn't be too hard.

 

[tntatro]

I just went out and made four milling cuts ranging from 8 to 16 inches wide and it didn't die on me. It's definitely back to having the idle and chain advance problem. It's also back to changing idle speed when turned on its side. When I put the new piston in I forgot to do a pressure/vac test, maybe it has a leak now.

Next I'll check out the piston to see if it's still looking good and then turn the flywheel back to where it was when it idled well but died on me to see if it was the other flywheel causing problems. I'll also do a pressure/vac test. I suspect it's actually something to do with the carburetor causing the change in idle speed when turned.

I'll switch carburetors with one of the magnums for a while. I'll put a Walbro carb on instead of Tillotson. The Walbro seems to be going nicely on the magnum so I think it will give a good indication if the carb is causing problems based on how both run after.

 

[Okie]

What I usually find whenachainsaw idling changes as the saw is rotated or laid on it's side.

If the idle changes when laid on it's side is usually a crankshaft seal just starting to leak.
Sometimes you can get a hint by just loosening the chain up and it will idle more consistent and idle changes as you tighten the chain if it's the clutch side seal. (tightening chain makes a old dried out seal leak little bit more even thou the bearing is still ok)
I've had old saws running real good without a bar and chain attached on the power head, install and tension the chain and the idling gets erratic and if still idling will get erratic more so if the saw is laid on it's side with clutch down and doing a pressure test will usually reveal a clutch side seal leaking as the crank is rotated and the bearing is still ok.
First couple times I seen such about idling changing when laid on it's side I suspected bad carb but have never seen a carb yet cause such.

 

[tntatro]

What I usually find whenachainsaw idling changes as the saw is rotated or laid on it's side.

If the idle changes when laid on it's side is usually a crankshaft seal just starting to leak.
Sometimes you can get a hint by just loosening the chain up and it will idle more consistent and idle changes as you tighten the chain if it's the clutch side seal. (tightening chain makes a old dried out seal leak little bit more even thou the bearing is still ok)
I've had old saws running real good without a bar and chain attached on the power head, install and tension the chain and the idling gets erratic and if still idling will get erratic more so if the saw is laid on it's side with clutch down and doing a pressure test will usually reveal a clutch side seal leaking as the crank is rotated and the bearing is still ok.
First couple times I seen such about idling changing when laid on it's side I suspected bad carb but have never seen a carb yet cause such.

I put new bearings in not too long ago. The clutch side seal was already in the bearing and the bearing and seal were new old stock. It is possible that I overheated the seal when installing the bearing onto the crankshaft but I did try to be careful. I've pressure/vac tested it several times but not since I put a new piston in. If the seals leak then it is only after it gets warmed up but I think the idle change can happen right after I start it if I turn it on its side. It's only 200 - 300 rpm change but with the idling problem it will stall.

 

[tntatro]

I tried switching my coil with another that failed the foggysail fix and it was the same. I also switched carburetors and nothing changed. I decided to put a points ignition in since I recently got a points flywheel in a box of parts. Upon disassembling I found that the switch wire had a small hole worn in it so there was a possible shorting problem.

It starts and runs normal now except it seems to flood a little at idle and runs rich. I switched the foam filter material with a Uni Filter and it improved. I have to turn the H needle to 3/4 from stop to get it to run nice at full throttle. It was also like that with the other ignition. I thought it was a timing issue but maybe not. I suspect it was running rich then leaning out a little during a milling cut because the new piston I put in is badly worn after only three cuts from testing it with the last ignition. I thought it was timing issues also. I had to turn the L needle in a little also to keep it from flooding at idle.

I guess now I'll test it and see how things hold up before replacing the piston. I'll fix the switch wire and give the Nova II ignition another chance on the next build. I may even try a different type of module.

 

[Okie]

You say new piston is badly worn with only 3 cuts. You suspect leaning out.

I would look at 3 things due to piston scoring in short period of time.
Dust getting in thru intake or the EXHAUST.
Engine over speeding or running lean.

To detect a overheating of a cylinder I happened to have a 3M infrared thermometer (costs about $50 several years ago) that I use for several things, automotive engine troubleshooting such as cylinder temp balance, (a weak or dead 4 cycle engine cylinder will be colder than a good cylinder) block temperature due to bad thermostat or temp gauge not reading correctly, bearing temperatures, immediately checking air conditioner temps, hot spots due to bad connections in electrical circuits, mainly breaker boxes to name a few.

I had a 028 Stihl that seized up when making a long time run full bar cut in a big log. (saw freed up after it cooled and the piston looked ok)
Everyone suggested the saw was running lean and I needed to use a tach and make sure it was not over speeding due to being too lean. I bought a $70 2 cycle tach checked the saw rpm's as ok and took the tach and the IR thermometer to the big downed log for testing the saw. (just happened to think of the IR thermometer for checking the 2 cycle block temp) Tach indicated no over speeding in the cut or out of the cut, but the thermometer indicated the cylinder was heating up real fast in the full bar cut as compared to other saws. The temp would start climbing real fast and I would back out of the cut so the saw would cool before reaching 400 Degrees F.

The other test saws would eventually reach around 360 degrees in a full cut and not get their fast doing the full bar cut as compared to the Stihl 028 saw that had seized.
The thermometer was easy to use by myself safely, just lay the saw in the cut and while cutting the downed log aim the red dot into the cylinder fins and monitor the temp.
A 1/4 turn in adjustment of the H jet corrected the overheat issue and the saw runs and cuts great. The saw now briefly 4 cycles for about one or 2 seconds when first placed into a full bar cut then smooths out a gets er dun.

I've checked several saws cylinder operating temp since and the average block temp of the cylinder that I have tested averages at very maximum around 340-360 degrees and temp does not get their very fast in a full bar cut with a sharp chain.
(engine loaded good and not over speeding)

You might think about acquiring a good IR temp tester and do a monitor of the cylinder temp of your saw in the long continuous milling cuts. I did not notice the saw overheating in minor cuts when the saw was not loaded up for very long. If I had not used the IR temp gauge I'm almost certain I would have ruined the saw. The carb jets were set at factory recommended setting for the saw initially and the tach indicated all ok and the saw ran great, but was too lean in the cut.

 

[tntatro]

You say new piston is badly worn with only 3 cuts. You suspect leaning out.

I would look at 3 things due to piston scoring in short period of time.
Dust getting in thru intake or the EXHAUST.
Engine over speeding or running lean.

To detect a overheating of a cylinder I happened to have a 3M infrared thermometer (costs about $50 several years ago) that I use for several things, automotive engine troubleshooting such as cylinder temp balance, (a weak or dead 4 cycle engine cylinder will be colder than a good cylinder) block temperature due to bad thermostat or temp gauge not reading correctly, bearing temperatures, immediately checking air conditioner temps, hot spots due to bad connections in electrical circuits, mainly breaker boxes to name a few.

I had a 028 Stihl that seized up when making a long time run full bar cut in a big log. (saw freed up after it cooled and the piston looked ok)
Everyone suggested the saw was running lean and I needed to use a tach and make sure it was not over speeding due to being too lean. I bought a $70 2 cycle tach checked the saw rpm's as ok and took the tach and the IR thermometer to the big downed log for testing the saw. (just happened to think of the IR thermometer for checking the 2 cycle block temp) Tach indicated no over speeding in the cut or out of the cut, but the thermometer indicated the cylinder was heating up real fast in the full bar cut as compared to other saws. The temp would start climbing real fast and I would back out of the cut so the saw would cool before reaching 400 Degrees F.

The other test saws would eventually reach around 360 degrees in a full cut and not get their fast doing the full bar cut as compared to the Stihl 028 saw that had seized.
The thermometer was easy to use by myself safely, just lay the saw in the cut and while cutting the downed log aim the red dot into the cylinder fins and monitor the temp.
A 1/4 turn in adjustment of the H jet corrected the overheat issue and the saw runs and cuts great. The saw now briefly 4 cycles for about one or 2 seconds when first placed into a full bar cut then smooths out a gets er dun.

I've checked several saws cylinder operating temp since and the average block temp of the cylinder that I have tested averages at very maximum around 340-360 degrees and temp does not get their very fast in a full bar cut with a sharp chain.
(engine loaded good and not over speeding)

You might think about acquiring a good IR temp tester and do a monitor of the cylinder temp of your saw in the long continuous milling cuts. I did not notice the saw overheating in minor cuts when the saw was not loaded up for very long. If I had not used the IR temp gauge I'm almost certain I would have ruined the saw. The carb jets were set at factory recommended setting for the saw initially and the tach indicated all ok and the saw ran great, but was too lean in the cut.

Thanks for the suggestion. I think an infrared thermometer could have likely saved a couple pistons on this saw. The first piston was scored already when I got the saw but was significantly worse after running it just a few cuts. Then I replaced it with a lightly used aftermarket and the same happened. The tuning isn't consistent with others saws I've had. It's an old carb but the factory settings are 1 turn out with L and 1 - 1/8 turn with H. This saw will flood at those setting at idle and 4 cycle hard at full throttle. I tried a different carb and it was about the same but it was also an old carb with an old kit. The one on the saw at least has a new rebuild.

My theory on what happened was I kept the L at factory setting and leaned the H so it sounded good at full throttle. The flooding at idle made it 4 cycle too much at full throttle but maybe during a long cut it would lean out as the excess gas burned off. I turned the L to around 3/4 and it doesn't seem to flood as much. I'll be testing it today a little.

The chain advance and idle problem seem to have gone away with the new ignition. I thought all the problems were a result of the ignition problems. I'll test it carefully and see if it looks good before replacing the piston. If I keep trying to fix up old saws I'll have to get one of those infrared thermometers.

 

[Okie]

I would try to run the saw on the big long full throttle cuts with the Jets, especially the H jet out (CCW) as far as possible.
The further in or CW the leaner she is.
Gasoline hitting the piston is what keeps em cool.

My 3M IR thermometer is a IR-500 and is approx. 15 years old. Very user friendly fits into shirt pocket, uses a 9v bat.
Mine will read temps at a range of approx. 15 ft. You can see the push button to read red dot where it's aimed when taking the temp. I think it's suggested to be within 4 ft of the object it's reading.

I think the 3M IR-500 are still around for about $50. Well worth the price to help save a Stihl saw before a melt down.

I'm not up on the latest versions or IR's and have not tried the cheaper HF types.

 

[tntatro]

I think you meant the opposite with the H adjustments. I ran it as rich as I could today with a few milling cuts and it seemed to be fine. I haven't inspected the piston yet. I ran it about 10,000 rpm. I usually run these saws around 10,500 - 11,000 rpm. I'll check out the piston and if there is no further damage I'll go between 10,500 to 11,000 rpm and maybe mill a log and see what happens.

This infrared thermometer goes for $17. Etekcity Lasergrip 774 Non-contact Digital Laser Infrared Thermometer. It has pretty good reviews too. I'm considering getting it but there are so many other things I should spend my money on right now. I was going to add a link to it but I wasn't sure if that is allowed. The 3M IR-500 is like $175.

 

[Okie]

I think you meant the opposite with the H adjustments. I ran it as rich as I could today with a few milling cuts and it seemed to be fine. I haven't inspected the piston yet. I ran it about 10,000 rpm. I usually run these saws around 10,500 - 11,000 rpm. I'll check out the piston and if there is no further damage I'll go between 10,500 to 11,000 rpm and maybe mill a log and see what happens.

This infrared thermometer goes for $17. Etekcity Lasergrip 774 Non-contact Digital Laser Infrared Thermometer. It has pretty good reviews too. I'm considering getting it but there are so many other things I should spend my money on right now. I was going to add a link to it but I wasn't sure if that is allowed. The 3M IR-500 is like $175.

Right I had it ass backards.

I went back and edited.

A 1/2 turn further out on the H jet corrected the heating issue and the saw briefly for about 2 seconds 4 cycle when first loaded into a heavy cut then just smooth out a pull big chips.

 

[tntatro]

It seemed like this one 4 cycles in the cut unless I push it a little more than normal although I was only milling 8" - 10" wide pine. I also think it would have a little more power with a slightly leaner adjustment.

I checked the intake side of the piston and it appears as thought the piston scoring is consistent with how the original piston was scored. The scoring is mostly on the right side and only on the bottom half of the piston. I won't be able to confirm it until I remove the piston but it almost seems as thought the bottom of the intake port may have formed a burr from the original damage to the piston. Either that or maybe there is too much play in the piston and it's catching the skirt on the bottom of the intake. I believe damage to the bottom of the intake could cause timing issues also.

 

[Okie]

It seemed like this one 4 cycles in the cut unless I push it a little more than normal although I was only milling 8" - 10" wide pine. I also think it would have a little more power with a slightly leaner adjustment.

I checked the intake side of the piston and it appears as thought the piston scoring is consistent with how the original piston was scored. The scoring is mostly on the right side and only on the bottom half of the piston. I won't be able to confirm it until I remove the piston but it almost seems as thought the bottom of the intake port may have formed a burr from the original damage to the piston. Either that or maybe there is too much play in the piston and it's catching the skirt on the bottom of the intake. I believe damage to the bottom of the intake could cause timing issues also.