SUCCESS!!! Just repaired Stihl 045/056 Bosch electronic ignition!!!!!

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Thank you. I see the WIMA caps below the Philips in your link. I actually have a couple of those. Hafta cross ref the specs to see if they may fly as well. I got them some time ago for an 031 ignition conversion that never occurred and completely forgot about them until seeing them in the link.
Good luck with the oil leak!
 
......Just an update to the Foggy Fix.....My 056Super is still running great after the fix quite a few months back.......I run it hard with a 36" bar on it, and it doesnt skip a beat!
 
I just got done with this repair and now I don't have any spark. I think the coil is bad and it's only showing 2k Ohms when I think it should be higher at about 8k Ohms. I wanted to know if the coil for the points 056 ignition will work if I solder it in. It looks like the physical dimensions and two screw holes are the same. The listings on Ebay says the 056 points coil will not work on the Bosch and SEM ignitions but I've never had any problems using OEM coils in Chevy engines that had points ignitions when converting them to Mallory Unilite optical trigger systems. I'm hoping the 056 points coils have the same resistance as the Bosch electronic ones.
 
Well she ran fine today until it started bogging down a couple of times then stalled & wouldn't fire again.
Pull starter cord and screeching sound.
Stripped again to find woodruff key broken so that explains the screeching....
Why would a woodruff key break, age???
 
Bear in mind that the force of the flywheel nut against the flywheel on the tapered crankshaft is where the strength of the entire attachment is derived. The key is primarily for timing alignment and only a marginal safety feature for the crankshaft in the event it somehow experiences excessive rotational torque. It has nothing to do with how tight the flywheel is. That said, and if the flywheel and crank keyways aren't hogged out, you can obviously just replace the key and probably be fine. In the meantime you could also carefully scribe a line on both the end of the crankshaft and face of the flywheel which correspond to the center of the keyways. Line them up and reinstall the flywheel to see if it still runs close to normal again.
 
On another note, what fuel mix for this saw?
I've been running 50:1 same as my ms231 but been advised its too lean.
 
I run 40:1 (ethanol free) for a little extra lower end protection in all my saws, but 50:1 tuned a little rich shouldn't hurt anything unless the saw is doing major milling or heavy bucking duty. I would then err on the side of caution with a richer fuel/oil mix..., using a high quality synthetic in either case.
 
Well she's back
Treated her to a new chain , need filters then carb setting up properly (running erratic, so thinking fuel)
Thanks for advice dudes
 
Welcome everyone.
.....For those inquiring minds about the inside of the Bosch Ignition........see pic..........Also the blue thing is the cap that goes bad.....VERY cheaply made...actual value is .8uf/400voltsView attachment 546687
I present the original cdi circuit:
Dolmar 119 cdi.PNG


Link:https://elektrotanya.com/stihl_045_tirisztoros_gyujtas_lancfuresz.pdf/download.html

Original SCR(BBC CS1.1-05do7F) is not available. Cross reference type BT151/650R recommend.
Use type CBB 22 condenser.
Hungary is a contractor to renovate the circuits:


Regards nyemi
 

Attachments

  • bbc_thyristor_catalog_1985-86.pdf
    4.8 MB
THE FIX!!!!

This may be a little verbose but my intent is to convey all that is needed to implement the fix. So first, I will start with a failed ignition showing and describing the repair steps. The tools you will need are: soldering iron....25 watts should work using solder designed for electronic work NOT PLUMBING SOLDER, I recommend an inexpensive heat gun...Harbor Freight maybe but with care you can work without one, epoxy designed for plastics.... HD or Lowes for about $5, electric drill with a 1/4 or so bit, a wire crimp tool with a lug (see pictures), and last I used a hot glue gun to sort of seal up the mounted new capacitor. The hot glue I used is industrial quality and you can get by substituting caulking selected from one of the many types available. And of course both a blade and Philips screwdriver will come in handy.View attachment 348005

Heat the small section as shown in the above picture, try to avoid heating the pulse transformer. The potting does not have to melt, just soften so a small section can be removed with a screwdriver or other suitable tool.
View attachment 348006

DON'T GET CARRIED AWAY chipping out that potting material! Take you time doing this. In teh above picture you see the shinny tinned copper PC run. The next picture will show where I want you to cut. Try to leave about 1/8" gap.
View attachment 348005 View attachment 348006 View attachment 348007

Heat up your soldering iron and get ready to solder an insulated wire onto the right hand side of the exposed PC bus (not the short piece to the left). I salvaged my wire from an old computer power supply and because I added 3 wires, I used two different colors so I could tell which went where. 18 gauge stranded wire will work fine. Please! Don't use a length of solid core house wire, your asking for trouble.View attachment 348009

I tucked that yellow wire under the pulse transformer. There is another wire that you add using a crimped lug. Secure it under the screw (holding the pulse transformer) above where you made your cut. Don't tighten the screw yet. Later when you install the ignition that lug will be in the way trying to get the mounting screw into the saw proper. That is when you will tighten the lug down. OH-- avoid using the yellow sized lugs. They are much larger and can get in the way of the rotating flywheel. Adding a third wire is entirely up to you, I used black so I would not mix it with the others. I cut the shutdown wire that goes to the on/off switch and replaced it with this third wire. If you don't bother replacing the shutdown wire, take care that the old wire's insulation is intact, cover it, tape it or just cut it out, it your decision. Remember if you disable that wire, you disable the on/off circuit to shut the saw off.View attachment 348012

Now here is where each of you can add value! I squeezed all three wires into the shared hole with the spark plug wire. There is a rubber grommet in the hole so they can be made to fit. Maybe you want to drill a new hole....???? Anyway, that is left for you to decide. After pushing the wires into the grommet, I used a piece of steel wire... coat hanger will work... shaped with a hook on the end to fish the wires out. Next I drilled 3 holes in the plastic air shield....1/4" or thereaboiut should work. Tow of the holes is for a tie wrap that I used to hold the new capacitor in place. The other hole is for the two yellow wires to pass through. Note I left the wires on the outside of the plastic to avoid them getting caught with the flywheel's fan. That's why you need to drill a hole for the wires.

View attachment 348013

Scrub the plastic under the tie wrap with alcohol and also scrub the new capacitor with the same. Mix up your epoxy. Paint generous amount of epoxy across the section under the tie wrap and on one side of the new capacitor. The capacitor will seat under the tie wrap with its two wire terminals pointing downward toward the flywheel. MAKE SURE you seat that cap such that it has space for the wires to be soldered to the terminals such that they don't get damaged by the fan. That is important! After pushing the new cap into place, tighten up on the tie wrap. Next pull both yellow wires into place and cut them leaving enough length to strip 1/4" or so needed to solder one wire to each terminal.

View attachment 348022

I used my trusty old, beat up glue gun to bury the new capacitor along with the new wires with hot glue. This ensures they will not move about with the saw's vibration.


View attachment 348016


View attachment 348021


IF YOU GOT THIS FAR---------- YOU HAVE COMPLETED THE FIX!!!!!!!!!!

You can test the fix after the epoxy dries along with the hot glue or caulking or whatever you select to use.

Assemble the saw so you can pull the starter rope....remove the spark plug from the engine, clip a grounding wire to it and pull the starting rope. If things go well, you should have a nice blue spark!

Will try to answer any questions-- Good luck, you can do it! Its not brain surgery!

Foggy[/QUOTE
Do you actually cut through the PC run?
 
I just read through all 33 pages (657 posts). REALLY was hoping someone found the fix for the SEM modules.
Did I miss that post somewhere?
 
Well low and behold! I baked my SEM coil at 250F for an hour and i have SPARK! Seems to take some rpm's to get it but it's definitely there fat and blue!
How long it will last remains to be seen.
 
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