A shocking experience, old Sthil

[Sprig]

My wee beast of much usage seems to have developed a bad habit, it started shocking me from contact with the plug wire. Its an old O8s and my baby, never did this quite like this before. There are no bare wires (worn spots contacting the case) and the exposed wire from the casing has been wrapped in electrical stretch rubber, the shock went through this (and me, its a pretty good zap esp in a face-cut). It is very distracting which makes it dangerous to me. I am scratching my head here because the wire appears solid (no bare parts touching anything etc), so I am asking the pros, what should I consider looking at when I pull it apart? The ground appears ok too btw. Other than getting a new saw, which I can't do, is there something that goes wrong that would cause this to happen, it has me scratching my head and wrist. Are there some tests I can do with a meter that could help me figure this out? I am thinking the coil (capacitor?) is maybe going south on me but have no experience with this sort of thing, any suggestions as to what may be causing this would be greatly appreciated.

Thankyou very much in advance good saw folks!



Serge
(edit)
I should add that the saw is running just fine when this happens (my wrist touching the wire that is), the shock is definately more WOT than at idle too.

 

[THALL10326]

My wee beast of much usage seems to have developed a bad habit, it started shocking me from contact with the plug wire. Its an old O8s and my baby, never did this quite like this before. There are no bare wires (worn spots contacting the case) and the exposed wire from the casing has been wrapped in electrical stretch rubber, the shock went through this (and me, its a pretty good zap esp in a face-cut). It is very distracting which makes it dangerous to me. I am scratching my head here because the wire appears solid (no bare parts touching anything etc), so I am asking the pros, what should I consider looking at when I pull it apart? The ground appears ok too btw. Other than getting a new saw, which I can't do, is there something that goes wrong that would cause this to happen, it has me scratching my head and wrist. Are there some tests I can do with a meter that could help me figure this out? I am thinking the coil (capacitor?) is maybe going south on me but have no experience with this sort of thing, any suggestions as to what may be causing this would be greatly appreciated.

Thankyou very much in advance good saw folks!



Serge
(edit)
I should add that the saw is running just fine when this happens (my wrist touching the wire that is), the shock is definately more WOT than at idle too.

That is odd indeed. If it were me I would take the spark wire and bend it all over trying to expose a slight crack that won't be visiable untill you bend it open. If the wire is free of all cracks and its completely insulating the current from the coil, it should not shock. Very odd problem you raise, thats a new one to me as well as you. Try the bending the wire all over and search it close for cracks. Also squeeze the spark plug boot as well searching for open areas(cracks)as well.....

 

[pbtree]

I am not certain of the cost, but I would venture it is a safe bet to change the wire and boot to the plug - I agree with Thall - there is probably a fine crack somewhere that is allowing the current to arc out...

 

[Sprig]

Thankyou guys for the quick responses!
What has me puzzled is that I have the wire wrapped in 1/8th in of rubber, so it seems it could very well be something near the cap and I'm sure that needs replacement anyhow. It makes me wonder how I am getting pooked from the side of the over insulated wire. It is very disconcerting to say the least. btw, this is in dry conditions, no damp so ta speak. I have it half apart and will go deeper too, but will order/find a new boot as I think this is origional one (circa 67). The old grey wire seems fine so far, through the grommets (2) etc.., I am wondering if the age of the wire itself has anything to do with this thing? Really dunno. So another question here, if it is the last 6" of plug wire is there a good way of replacing that section? What sort of connections should I use ( ie. shrink wrap etc. ?), would that work or should I look at replacing the whole length? Open to suggestions here man, gotta get it right, or working, or both.

 

[bcorradi]

Hey Sprig

Yeah if i was you i would just replace the boot and the wire all in one shot. Lakeside will tell you exactly what length and diameter wire you would need.
Take care,
Brad

 

[Sprig]

bcorradi, thanks to you and all, will do. Being a generally lazy bugger I had hoped it was simpler lolol. But I think you're all right.

Thankyou!



Serge

 

[oneadam12]

I have never dealt with this problem on a saw before, but have seen it several times on vehicles. This insulation on the wires loses its dielectric strength(insulation value) with age. A lot of the time it is extremely hard to find a crack or pinhole. A good way to check is at night or in a very dark room, but watch out for the exhaust fumes.

 

[BlueRidgeMark]

A good way to check is at night or in a very dark room,

Why bother? We're talking about pennies of cash and minutes of time. Just replace it!

 

[oneadam12]

true, but it seemed sprig wanted a possible explanation.

 

[lovetheoutdoors]

Sprig i hope you get this fixed.....that would suck getting zapped.:bang:

 

[Sprig]

Update

Simple fix, not minutes to fix but fairly straight forward, I downloaded a manual for it a while back and its a matter of just doing it now, I was having a bit of trouble with the flywheel and it is soaking in WD-40 right now (the nut that is). I'll break it this evening when I have the time and check the other components while I'm in there.
On close inspection of the plug wire I found several very, very small holes where it had obviously been arcing out (and into me, man that truly did suxor I tell ya, esp. as I was in the middle of a fall and buck gig) smaller than this >.<, very hard to detect with unaided eyes. Very glad it is only that.

Cheers all! Skoll!

Serge

 

[Justsaws]

I shocked myself good late last night with a Stihl 075. Woke me up fast. Replaced all the wires, I figure if one has gone bad the rest are soon to follow. Some saw dealers sell the sparkplug wire by the foot. Hope you get your saw fixed.

 

[THALL10326]

Simple fix, not minutes to fix but fairly straight forward, I downloaded a manual for it a while back and its a matter of just doing it now, I was having a bit of trouble with the flywheel and it is soaking in WD-40 right now (the nut that is). I'll break it this evening when I have the time and check the other components while I'm in there.
On close inspection of the plug wire I found several very, very small holes where it had obviously been arcing out (and into me, man that truly did suxor I tell ya, esp. as I was in the middle of a fall and buck gig) smaller than this >.<, very hard to detect with unaided eyes. Very glad it is only that.

Cheers all! Skoll!

Serge

Good job Sprig, I knew you would find the problem, good job indeed........

 

[04ultra]

Sprig