I've have owned a Stihl 041 super AVE for 35 years and it finally died from a "no-spark" condition. This one has the SEM version of the electronic ignition. Researching the forums and looking on fleabay, I am unable to locate a replacement SEM coil. I believe the coil is an SEM Type GA coi which is used on Husky 2100's and some Dolmarsl, but I haven't pulled the flywheel yet. Any suggestions for replacement coils or other other solutions to make a spark at the right time? The saw ran really strong, excellent compression; the piston and cylinder show no scoring, so I'd prefer to fix it than junk it or sell it for parts. Thanks in advance for responses.
Stihl 041 Super AVE - No Spark - SEM Electronic Ignition
- Thread starter vision976
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Im in the same dilema as you.
Kash
Kash
The Dolmar 309 cut off saws/ demo saws used the same coils I do believe and since their pistons and cylinders didn`t last long breathing in concrete dust there were a lot of those coils around , I had no troubles rounding up a few as spare parts for my Dolmar 133 and several 041`s of both AV and FB models.
No, the Stihl 041 series never used the SEM GAs.
You need an early GE type & they do show up on auction sites every now & then.
You need an early GE type & they do show up on auction sites every now & then.
Thanks for the tip; I bought a used Dolmar 309 coil off of fleabay last night. Will report back on success or failure once I receive it and install it.
I think the other option would be to convert it to points & condensor (which would be a satisfactory solution). I'd just have to find the stator plate with coil, condensor and the proper flywheel.
Thanks for the clarification of the type of SEM coil needed. I don't know which is the more useful: the Internet and forums like this one, or the instructional videos found on YouTube. I appreciate everyone's feedback in helping me to bring life back into the old 041 Super.
Yes, please do. I have squirreled away a couple spares if my 041`s ever need them but I actually bought them to fix my Sachs Dolmar 133 and as a spare for my SD120S . The 041`s have never lost spark so far but I hear its a common thing with them.
Please keep us informed of your sucsess or failure.
Thanks Kash
Thanks Kash
Will do. I'm waiting for the coil and the flywheel puller to arrive.
Meantime, I bought a new 500i yesterday to replace the 041 Super. Dang thing came with a 32" bar! Talk about unwieldy. Plus it's a little "nose-heavy" with that long a bar on it. I'll buy a 25" ES bar for it; I've hefted one of those and it isn't nose heavy.
John
I have heard lots of glowing reports on the 500i , only thing bad is they use a lot of fuel. Guys bucking with them in the woodlots love them.
Yes, I had read that about the 500i. I don't know why it would be any thirstier than a carbureted saw of the same 6.7 HP level. Usually fuel injected cars get better gas mileage than carbureted models. Since I'm not packing that thing around on my back when I'm cutting deadfalls on the Forest Service roads, 4x4 trails or single tracks (I have a pair of McCulloch MiniMacs I use and maintain for that purpose), fuel consumption won't be an issue. It will fit easily with the 25 inch bar in the back of my Wrangler. The forest fire season of 2012 here in the NW killed a lot of timber and much of it is standing rotten by this time. When the big autumn storms come through, the rotten timber comes down.
By the way, the old 041 Super with the 24" b/c weighs just shy of 22 lbs. It balances perfectly at the top handle.
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That is indeed the fastest way to get er up and running. You can buy the entire ignition set up including the stator plate for around 100 bucks on the bay. The flywheel (and rotor) probably 60 more. It bolts right in. Set your points to around .017 and use the original position (as indicated by the marks left by screws) for you stator and it will run. I so much prefer the magneto ignition to the electronic. I have a complete set up as described stashed away should I ever need it. I have an 041 AVEQ that runs for the moment.
I received my flywheel puller and used it to access the coil. The coil checks out in terms of primary and secondary resistance when checked with an ohm meter. 0.4 Ohm primary and 2.7K ohm secondary. This saw did not demonstrate a "hot-start" problem, it just quit running and would not even pop with starting fluid. So I am suspecting that it may be a bad capacitor within the potting compound as described elsewhere on this forum, relative to the 056 and 041 ignition problems. Still waiting for my Dolmar coil to arrive.
Still waiting for the Dolmar coil to arrive. Reseaching the SEM and Bosch electronic ignitions issues, and finding the Bosch capacitor trigger fix Foggysail documented on this forum years ago, makes me wonder if the SEM and Bosch ignition modules are designed the same way. Does anyone know if Stihl designed the ignition module circuit and then farmed it out to SEM and Bosch for production?
The pictures of the Bosch ignition module I have found, look identical to the SEM module. Same shaped aluminum "can" filled with potting compound. So I am wondering if I can apply Foggsail's external capacitor solution to the SEM module.
It's pretty clear to me that there are multiple solutions to the "no-spark" problem I'm trying to fix:
The pictures of the Bosch ignition module I have found, look identical to the SEM module. Same shaped aluminum "can" filled with potting compound. So I am wondering if I can apply Foggsail's external capacitor solution to the SEM module.
It's pretty clear to me that there are multiple solutions to the "no-spark" problem I'm trying to fix:
- Replace the defective SEM ignition module with a used, good one from various saws
- Replace the SEM ignition module and flywheel with a Bosch ignition module and flywheel
- Fix a bad Bosch ignition module per Foggysail's solution; install that module and flywheel
- Convert the saw to use a Stihl stator plate, points, condensor and flywheel
UPdate: 12/28/2021
Received SEM Ignition Module from eBay purchase from a Dolmar 309 Concrete saw. To fit it to Stihl 041 Super, it was necessary to have shorter M40 .70 screws. Stator plate holes aligned with 041 Super stator mounting plate holes. Necessary to mill a groove for the shut-off switch wire to pass through under the stator plate to the exit hole in the motor casing to reach the switch. Yellow switch lead is too short to reach the 041 shutoff switch and would require lengthening.
Dolmar SEM G/E ignition module high tension lead is too short to reach the 041 super spark plug. It is permanently fixed into the ignition module and cannot be unscrewed, unlike the stock SEM high tension lead. Would require a high tension lead splice, not a big deal.
It is not quite as tall as the stock SEM ignition module, about 1/10 of an inch shorter in height. It fits under the SEM flywheel without rubbing anywhere.
With it installed correctly (properly torqued down), I re-installed the flywheel and spun it up in the correct direction of rotation. I held the end of the high tension lead close to the cylinder head, watching for the spark. Did not see any. I dimmed the lights in the shop and spun the flywheel/crankshaft again, without a sparkplug installed. I saw the a very weak spark traveling between the wires of the high tension lead and the cylinder head. I installed a fresh battery pack in my drill, and spun the assembly up again. No spark this time. I varied the distance between between the wires in the high tension lead and the cylinder head, but no spark would appear. I tried several times. No spark.
What do I conclude?: I'm not sure the Dolmar SEM 309 coil will ever work to solve the no-spark situation I have in my Stihl 041 Super. At least not with the original SEM flywheel that came with the saw. The problem could be the SEM ignition unit being defective as it was "used". I don't know how to test it; the eBayer I bought it from, said it was "good", but there's a crack in the housing of the unit, that might have allowed something to enter the potting area, or even cracked a circuit board inside the unit.
I don't know.
Also, the location of the laminated iron plates which gather the flux lines from the magnets in the flywheel when it spins, are not located in precisely the same locations as the ones on the SEM original stator plate, so it is possible that not being the same relationship, the correct voltages necessary to fire a spark are available. I will post pictures tomorrow, showing the differences.
I don't think this suggested solution will bear fruit.
More tomorrow.
Received SEM Ignition Module from eBay purchase from a Dolmar 309 Concrete saw. To fit it to Stihl 041 Super, it was necessary to have shorter M40 .70 screws. Stator plate holes aligned with 041 Super stator mounting plate holes. Necessary to mill a groove for the shut-off switch wire to pass through under the stator plate to the exit hole in the motor casing to reach the switch. Yellow switch lead is too short to reach the 041 shutoff switch and would require lengthening.
Dolmar SEM G/E ignition module high tension lead is too short to reach the 041 super spark plug. It is permanently fixed into the ignition module and cannot be unscrewed, unlike the stock SEM high tension lead. Would require a high tension lead splice, not a big deal.
It is not quite as tall as the stock SEM ignition module, about 1/10 of an inch shorter in height. It fits under the SEM flywheel without rubbing anywhere.
With it installed correctly (properly torqued down), I re-installed the flywheel and spun it up in the correct direction of rotation. I held the end of the high tension lead close to the cylinder head, watching for the spark. Did not see any. I dimmed the lights in the shop and spun the flywheel/crankshaft again, without a sparkplug installed. I saw the a very weak spark traveling between the wires of the high tension lead and the cylinder head. I installed a fresh battery pack in my drill, and spun the assembly up again. No spark this time. I varied the distance between between the wires in the high tension lead and the cylinder head, but no spark would appear. I tried several times. No spark.
What do I conclude?: I'm not sure the Dolmar SEM 309 coil will ever work to solve the no-spark situation I have in my Stihl 041 Super. At least not with the original SEM flywheel that came with the saw. The problem could be the SEM ignition unit being defective as it was "used". I don't know how to test it; the eBayer I bought it from, said it was "good", but there's a crack in the housing of the unit, that might have allowed something to enter the potting area, or even cracked a circuit board inside the unit.
I don't know.
Also, the location of the laminated iron plates which gather the flux lines from the magnets in the flywheel when it spins, are not located in precisely the same locations as the ones on the SEM original stator plate, so it is possible that not being the same relationship, the correct voltages necessary to fire a spark are available. I will post pictures tomorrow, showing the differences.
I don't think this suggested solution will bear fruit.
More tomorrow.
That’s a lot of coil modification work for no spark!
When you get a chance, post some close-up photos of the Dolmar ignition & the inside of your current S041AVE flywheel.
When you get a chance, post some close-up photos of the Dolmar ignition & the inside of your current S041AVE flywheel.
Photos: SEM Stihl Flywheel 100 468 00, inside of flywheel; north pole magnet denoted by south pole of compass needle attraction, south pole magnet denoted by north pole of compass needle. The other two "magnet appearing" weights across the inside of the flywheel are not magnitized, they are strictly counter-weights to the North and South pole magnets.
4th image is of the Dolmar coil resting in the 041 installation location; you can see the yellow switch-off lead is laying in a notch I cut to ensure it cleared the underside of the flywheel rim.
5th image shows the crack in the Dolmar coil (filled with white concrete dust). Perhaps the coil has internal damage.
6th image shows side view of the Dolmar ignition module stacked directly above the SEM electronic ignition module with the stator plate mounting holes aligned vertically. You can see the iron plates used to generate current when the magnetic flux lines pass by from the rotating flywheel magnets. Note that the Dolmar module has two sets of iron plates close together, where the SEM module has it's number 1 and number 2 sets spread quite far apart.
7th image shows the same module stack from the right-side view: The SEM coil on the bottom, shows it's number 2 and number 3 iron plate sets are located on either side of the Dolmar module's 3rd iron plate set position. This makes me think the Dolmar flywheel must have a different collection of magnets than the SEM flywheel. Perhaps they are located differently along the perimeter of the Dolmar flywheel, as compared to the SEM flywheel This might explain why I was unsuccessful in getting consistent spark behavior; but perhaps the Dolmar module is defective anyway, since it does have a crack.
8th image shows plan view of the Stihl and Dolmar modules side by side.
9th image shows the Stihl module being boiled in water, in an effort to cause the epoxy potting to get to it's glass stage, so that I might be able to dig the compound out to expose the electronics. 212 degrees F, only slightly softened the epoxy, just enough to enable a screw driver tip to slightly dent when pushed hard. Ideally, if the epoxy were removed, then Foggysail's Bosch Ignition fix might be able to be implemented. (the external mounted 400 VDC .8MF capacitor solution). But alas, some higher temperature is needed to remove the epoxy.
Researching how to removed hardened epoxy potting, says methylene chloride solvent may be used to dissolve it. A 500 ml steel bottle can be had for $14 plus shipping. But that's nasty stuff to work with. I suspect it would take days of soaking and much mechanical effort to remove the potting. Methylene chloride would attack any plastic inside the epoxy coating and may attack the aluminum housing as well. Too much trouble.
I have bought an 041 points/condensor stator plate and flywheel off of eBay last night. So that may be the easiest way to restore a spark to the saw.
In conclusion, I think that the installation of a late model Dolmar SEM ignition module in place of the early model SEM module will not solve the "no-spark" problem. While the Dolmar unit I purchased might be defective, the location of the iron plate magnetic pickups being different between the two modules makes me think the original Stihl SEM flywheel would not work properly with the Dolmar ignition module.
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You are correct, just can’t mix the GE & GA SEM modules, without their correct flywheels.
Be patient & a good used or new SEM GE will show up on a popular auction site.
Be patient & a good used or new SEM GE will show up on a popular auction site.
So the question is whether there is a GA SEM flywheel that would fit the Stihl 041? Probably not, at least not one that would enable attaching the Stihl 041 fan to it.
Looking at the Dolmar SEM flywheels on Ebay, they seem to have a single magnet, much longer than either of the two in the Stihl SEM flywheel.
Probably a lost cause.
Not that I’ve ever seen.
You’d be time & money ahead to buy a used Bosch electronic 041flywheel from fleabay & then get the Seagenspezi new Bosch electronic replacement module. I don't know if they have started shipments back up from Germany yet, as they shut it down during 2020 covid. You can reuse the 3 screw fan wheel from your SEM flywheel.
https://shop.saegenspezi.de/electro...-and-Ducati-ignitions-fits-Stihl-041-AV-041AV
You’d be time & money ahead to buy a used Bosch electronic 041flywheel from fleabay & then get the Seagenspezi new Bosch electronic replacement module. I don't know if they have started shipments back up from Germany yet, as they shut it down during 2020 covid. You can reuse the 3 screw fan wheel from your SEM flywheel.
https://shop.saegenspezi.de/electro...-and-Ducati-ignitions-fits-Stihl-041-AV-041AV
