Only get Spark Spinning Backwards

[bob54]

It's a Stihl BG 86 and only has spark when you spin the flywheel backwards but not when spinning in the direction the recoil spins it. I have cleaned the flywheel as well as the Ignition module and set the air gap with a thin Business card. It made no difference still only get spark spinning in the wrong direction which makes no sensed to me. Anyone have any ideas?

 

[backhoelover]

the pole on the coil have switch. need a new coil.

 

[bob54]

How does that happen and any way to switch it back?

 

[Wilhelm]

the pole on the coil have switch. need a new coil.

Don't You mean the poles on the flywheel?
Magnet is on the flywheel right?
Would require a flywheel replacement in that case.

Not trying to be a smartass, just trying to help.
Cheers,
W.

 

[bob54]

That makes sense W, how can I tell? Anyone know which way the poles on the magnets should be in the flywheel

 

[backhoelover]

on the coil. one post makes it spark the other stops the spark. so if the pole on the coil are backward the one that makes it spark is now stopping spark and the one that stop spark is making it spark. only reason i know is when i went to stihl tech school a while back they was getting into ignition pretty heavy. to be honest they only way i know to check the flywheel is with a good one and a magnet and see if the pole are the same. they did go over the flywheel but to be honest i was paying more attention to the operation of the coil lol. i have a tech book for that school ill see if i cant find it and see if it says anything. if not ill give stihl tech a call monday and see if they can tell me something

 

[bob54]

Thanks backhoelover

 

[AVB]

on the coil. one post makes it spark the other stops the spark. so if the pole on the coil are backward the one that makes it spark is now stopping spark and the one that stop spark is making it spark. only reason i know is when i went to stihl tech school a while back they was getting into ignition pretty heavy. to be honest they only way i know to check the flywheel is with a good one and a magnet and see if the pole are the same. they did go over the flywheel but to be honest i was paying more attention to the operation of the coil lol. i have a tech book for that school ill see if i cant find it and see if it says anything. if not ill give stihl tech a call monday and see if they can tell me something

Are you kidding? That is not why it is not working. It is polarity of the generated magnetic field that does the triggering. Most modern today coils trigger on the positive pulse where older coils were triggered on the negative pulse. So when a coil is flipped upside down it can't trigger by the positive as it a negative pulse; unless you're spinning the flywheel backwards.

This is why the Nova II triggers need to be wired for positive ground sometimes on older equipment that you're replacing the points on and why older cast iron Briggs will not take new Magnatron coils.

 

[backhoelover]

not kidding. just going on what i been taught, if what i was told is wrong was not the first time and sure in the hell will not be the last. but you could have came off a little nicer in proving what i was taught was wrong.

 

[Czed]

not kidding. just going on what i been taught, if what i was told is wrong was not the first time and sure in the hell will not be the last. but you could have came off a little nicer in proving what i was taught was wrong.

That's what i was taught as well.

 

[AVB]

Sorry Guys, having one my bad days with headaches. Please I didn't mean to come off as hateful though it might have come out that way. At least I wasn't yelling though I think beating my head against a brick wall might feel better today.

Basically it is because they are using NPN transistors and not PNPs plus a capacitor if I remember correctly. Some are even driven by SCRs

Here is a good reference article.
https://www.bennettco.k12.sd.us/cms/lib/SD01001545/Centricity/Domain/223/SMALL ENGINE IGNITION SYSTEMS CH10.pdf

 

[backhoelover]

Sorry Guys, having one my bad days with headaches. Please I didn't mean to come off as hateful though it might have come out that way. At least I wasn't yelling though I think beating my head against a brick wall might feel better today.

Basically it is because they are using NPN transistors and not PNPs plus a capacitor if I remember correctly. Some are even driven by SCRs

Here is a good reference article.
https://www.bennettco.k12.sd.us/cms/lib/SD01001545/Centricity/Domain/223/SMALL ENGINE IGNITION SYSTEMS CH10.pdf[/QUOTE

been to dr? was having head aches and it was my neck. hope you get better

 

[backhoelover]

Sorry Guys, having one my bad days with headaches. Please I didn't mean to come off as hateful though it might have come out that way. At least I wasn't yelling though I think beating my head against a brick wall might feel better today.

Basically it is because they are using NPN transistors and not PNPs plus a capacitor if I remember correctly. Some are even driven by SCRs

Here is a good reference article.
https://www.bennettco.k12.sd.us/cms/lib/SD01001545/Centricity/Domain/223/SMALL ENGINE IGNITION SYSTEMS CH10.pdf

been to dr? i was having head ache was a muscle in my neck. hope you get better

 

[AVB]

Been having them for nearly 35 yrs. Most times I learn to catch them in time but this time it hit at 3 am in the morning and I have been working it for 2 days now. Getting better just takes time when I slip up.

When I first start having I did go to several docs none of them could find a problem; they just call them cluster headaches. I was up to 4 Tylenol tablets [close to overdosing] at a time then I found the Excedrin. I tried some others pills out there and none work as well. Usually they calm it down after the second or third dose. I going to need build myself another quite room underground. The dark cool quite place seems to do a lot good calming my head down.

I had to quit what I had scheduled today. I can put that 44M Briggs back together tomorrow. At least I got the Kawasaki Prairie ATV done before it got too bad today.

 

[Czed]

Been having them for nearly 35 yrs. Most times I learn to catch them in time but this time it hit at 3 am in the morning and I have been working it for 2 days now. Getting better just takes time when I slip up.

When I first start having I did go to several docs none of them could find a problem; they just call them cluster headaches. I was up to 4 Tylenol tablets [close to overdosing] at a time then I found the Excedrin. I tried some others pills out there and none work as well. Usually they calm it down after the second or third dose. I going to need build myself another quite room underground. The dark cool quite place seems to do a lot good calming my head down.

I had to quit what I had scheduled today. I can put that 44M Briggs back together tomorrow. At least I got the Kawasaki Prairie ATV done before it got too bad today.

My older brother has had cluster headache's for decade's every so often
It's misery.
nothing slows him down but those wipe him out.
Now he has 4 kids i don't know how he does it.
Luckily they are very rare now and appears to be curing itself.
Hopefully yours does the same.

 

[Likesaws]

Sorry Guys, having one my bad days with headaches. Please I didn't mean to come off as hateful though it might have come out that way. At least I wasn't yelling though I think beating my head against a brick wall might feel better today.

Basically it is because they are using NPN transistors and not PNPs plus a capacitor if I remember correctly. Some are even driven by SCRs

Here is a good reference article.
https://www.bennettco.k12.sd.us/cms/lib/SD01001545/Centricity/Domain/223/SMALL ENGINE IGNITION SYSTEMS CH10.pdf

Great read thanks for the link.