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

[echomeister]

Don't buy from Ebay. Can't tell what you are getting. This cap needs to be high frequency and high temp.
If this fits i would use it.

https://www.digikey.com/product-detail/en/kemet/R76PW410050HLJ/399-R76PW410050HLJ-ND/10428776

 

[9050LX]

I have had very good success with the NOS Russian military K series caps, sometimes sitting inches away from 400 degree power tubes. Recent manufacture Sprague/Vishay or Panasonic is prudent.This value of capacitor is ridiculously plentiful.Ebay allows you to buy a small amount without a large shipping cost.

 

[Vintage Engine Repairs]

I was generously gifted a Phillips cap from @scallywag on here. I really wanted to pass it forward and help someone else out. I have been looking high and low for something suitable and be able to send them to you guys that are struggling. Postage shouldn’t be very expensive and the caps are cheap. I finally found these, the only thing is I can’t confirm if they are pulse rated (it’s an online store so can’t call to ask)

@foggysail can you please confirm if this is suitable?

https://au.element14.com/illinois-capacitor/105mpr400k/capacitor-polypropylene-pp-film/dp/1666089
If so and anyone is really struggling for a cap, let me know, I’ll get a final price and send them out to you all. It may be better for me to send a bunch to one person to the USA to keep the postage costs down, then that person can then send them out individually?

Whatever is best for you guys.

 

[Vintage Engine Repairs]

Thanks @foggysail I completed the fix, it’s all still apart, but I used the drill to spin the flywheel and after a few seconds I got a lovely bright blue spark. The only thing I couldn’t do was get all 4 wires back through the grommet, instead I wrapped 3 layers of insulating tape around the wires popped them through.

@scallywag thank you for the capacitor mate, without your generosity in offering I wouldn’t have been able to complete the fix.

 

[PogoInTheWoods]

Nicely done!

 

[Vintage Engine Repairs]

Gentleman, I think i have found a supply of 477 capacitors! Wooooo @foggy, please have a quick look to confirm these will work, let me know and I will buy a batch. Then if anyone needs them I can send them out.

https://au.element14.com/kemet/r75m...p/2456384?st=pulse 1uf 400v mkp capacitors uk

 

[Vintage Engine Repairs]

Little update, I ran the saw for the first time after the capacitor fix, before it ran for a few cuts and died. Today after the fix I did 30 cuts and it didn’t stop once. It was running for about an hour and got nice and hot. I call that a success yay thanks foggy!

 

[PogoInTheWoods]

@foggy, please have a quick look to confirm these will work...,

I don't believe he monitors this thread any longer. It's been quite some time since he's posted here or responded to anyone. I'd say he probably figured his original contribution to the cause pretty much covered everything necessary and his effort had concluded after so many folks posted about their own success using his method and his recommended capacitor type and values.

It's great that those caps in your link work and is nice of you to share your resources and experience with using them.

 

[Vintage Engine Repairs]

I don't believe he monitors this thread any longer. It's been quite some time since he's posted here or responded to anyone. I'd say he probably figured his original contribution to the cause pretty much covered everything necessary and his effort had concluded after so many folks posted about their own success using his method and his recommended capacitor type and values.

It's great that those caps in your link work and is nice of you to share your resources and experience with using them.

Yes it’s totally understandable, the fix I did was with the blue philips caps not
The ones I linked to, I didn’t want to risk all that work without putting it past foggy. If I come accross another saw I’ll try the caps I linked to but wont pot it or glue it to the plastic shroud, instead just cable
Tie it and then I can easily remove it if necessary.

 

[Seadiver5]

I finally found this thread after owning my 056 for over 30 years it's developed what I believe is this problem. While I haven't read all the posts on this thread I'm wondering if there is anyone out there that has done this fix and had their saw working reliably for several years now? Before diving in to repair my saw I just want to know that the repair is pretty dependable for the long run.
Thanks

 

[PogoInTheWoods]

I'm wondering if there is anyone out there that has done this fix and had their saw working reliably for several years now?

This thread is over 6 years old with very few instances of failures being reported. I'd say the majority of folks who performed the fix according to the instructions and used the correct (or compatible) capacitor still have reliably performing ignitions.

 

[Seadiver5]

This thread is over 6 years old with very few instances of failures being reported. I'd say the majority folks who performed the fix according to the instructions and used the correct (or compatible) capacitor still have reliably performing ignitions.

Thanks for the response. All the failures that I read seemed to be immediate failures to the repair and my question was more related to the long term and preferably consistent use of the saw. I'm assuming as you have that the fix continues to work but I would just like to hear from some people that actually have made the repair that the fix did in fact continue to work correctly for the long haul. Thanks again.

 

[Vintage Engine Repairs]

Chaps, does the 045av capacitor in the ignition module have the same issues as the 056?

 

[Woodslasher]

I saw the 045 you’re working on Tom, you’ll be lucky if that isn’t a points setup. No, I don’t think any of the other coil types were prone to failure

 

[Vintage Engine Repairs]

I saw the 045 you’re working on Tom, you’ll be lucky if that isn’t a points setup. No, I don’t think any of the other coil types were prone to failure

Thanks mate excellent stuff, I hope so, but wasn’t certain and thanks for the reply on my other post!

 

[PogoInTheWoods]

An 045AV does indeed have a points ignition -- most likely Bosch. The saw in question from the other thread will definitely have points unless converted..., which appears highly unlikely. The 045 Bosch ignitions are completely serviceable (and desirable) with both NOS (some, anyway) and aftermarket components readily available. The exception would be flywheels which seem to be getting harder and harder to come by as folks convert back to points from the notoriously failure prone SEM electronic module. The SEM electronic module does not have an accessible internal capacitor like the Bosch electronic module, btw,

 

[BackhoeBill]

My stop switch wire was so bad it was corroded and falling apart. I unsoldered it from wherever it was attached. Can I solder a new wire to the black wired leg of the exciter coil? I circled where I think the connection is.

 

[PogoInTheWoods]

It's certainly the correct location for the kill wire entry point to the circuit. If that's indeed a solder lug you have circled, I'd say you're in the right place. You could do some metering to further determine if a switched short to ground of the ignition circuit would be established from that point..., perhaps directly to the adjacent lug. My guess would be yes. Please post your results. Aside from the capacitor issue with these ignitions, the kill wire problem is a close second in their premature death. Knowing where to attach a new one (with better insulation) at the circuit itself would be another valuable solution to giving these ignitions new life.

One of these days I'll repair this one to revive a nice old 056 I got cheap with a bad SEM ignition. Found this Bosch coil and accompanying flywheel locally..., shortly after finding this thread. Seems like something else has been in the way of getting to it ever since. Last project was rebuilding an 045, so I'm at least getting closer!

​

 

[BackhoeBill]

It's certainly the correct location for the kill wire entry point to the circuit. If that's indeed a solder lug you have circled, I'd say you're in the right place. You could do some metering to further determine if a switched short to ground of the ignition circuit would be established from that point..., perhaps directly to the adjacent lug. My guess would be yes. Please post your results. Aside from the capacitor issue with these ignitions, the kill wire problem is a close second in their premature death. Knowing where to attach a new one (with better insulation) at the circuit itself would be another valuable solution to giving these ignitions new life.

One of these days I'll repair this one to revive a nice old 056 I got cheap with a bad SEM ignition. Found this Bosch coil and accompanying flywheel locally..., shortly after finding this thread. Seems like something else has been in the way of getting to it ever since. Last project was rebuilding an 045, so I'm at least getting closer!

View attachment 880830​

It worked! That is definitely the right location, works great.

With the new capacitor the spark was so strong the spark plug wire insulation failed and sent 1/2" long sparks from the wire to the cylinder head. I knew I shoulda replaced that thing when I had everything apart. Now I get to take it all apart again.

 

[PogoInTheWoods]

I hope you don't burn a hole in your piston with all that spark. LOL

Out of curiosity, what capacitor did you use?