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Jobu 81808 no sparks

Stefancvij

Stefancvij

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Hey everyone. I am trying to fix an old chainsaw, its a old norwegian one called "Jobu 81808".The problem is that it doesnt give a spark. I have tried 2 different spark plugs, ive cleaned the contacts between the flywheel and the stator. I have tested the sparkplug cable, and i have cleaned every surface that is supposed to be connected to each other. While disassembling and assembling the saw numerous times, i got lucky and it sparked 5-6 times, but no more luck after that.
I cant find any manuals for this saw eather, if you search it you will see only links to museums, haha.

Under you will se a image of how everything is wired, i might also have connected the wires wrong, but this is how it was connected when i first took it apart.

Huge thanks to everyone that replies :)
 

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rd35

Just an average Joe's brother!!
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In the photo you posted, the large red part is your coil. The silver cylinder is your condenser. Directly below the condenser is a little set of contacts that open and close as the engine rotates. These contacts are called "points". Use a very fine grade of sand paper or emery cloth folded and inserted between the contacts to burnish and clean these contact points of any dirt, debris, or burnt surface material that can cause a bad electrical contact. When working properly these "points" will supply power to the coil to energize it. When the points open the power to the coil is interrupted. This loss of power to the primary side of the coil allow its magnetic field to collapse which generates a very high voltage in the secondary causing a spark to jump the gap on the spark plug. The adjustment of the gap on these points is critical as it affects engine timing. Also, if the adjustment is off too much they will either not open, or not close. Most likely, they are already adjusted reasonably close to correct.
 
HarleyT

HarleyT

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the contact surfaces should be buffed clean with a fine grit sandpaper first, then swiped clean with clean paper, then I'd try .016 to start.
 
Stefancvij

Stefancvij

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Ok, thank you both for the replies. I disassembled the whole thing so the points are most likely not adjusted properly.. But i dont think that this is the problem. We tried starting it by pulling the rope, no luck. We tried a second time, without adjusting anything and it gave sparks, then again nothing. So the points should work how they are adjusted right now, but i will adjust them correctly of course.
One thing i think is strange: I tried using a multimeter to see if the points had any contact, and strangely the multimeter beeped. If you look at the picture, the left point is connected to ground.. But so is the right one, it is connected to the condenser, so is the red wire from the stator, and the stator is connected to ground. Is this how it is supposed to be?
 
HarleyT

HarleyT

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They green cicle looks like a problem as well. Looks like someone tried to make that condenser work. The strap shouldn't be touching the side, and the nut should be tight.

points.jpg
 
Stefancvij

Stefancvij

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Oh i didnt know it wasnt supposed to touch the side, thanks. The strap is a littlebit short so i couldnt tighten it more without breaking something, but i checked it with the multimeter and everything should still have contact. I know it isnt optimal but i just want it to start for now
 
HarleyT

HarleyT

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That condenser doesn't look like it is supposed to be in there, you might try a different one with better luck.
Can you snap a pic of the whole saw?
 
HarleyT

HarleyT

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Here is a tecumseh condenser for example. There are shorter ones out there. But get one with the wire and terminal, and ger rid of that strap.

tec.jpg
 
ray benson

ray benson

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Hey everyone. I am trying to fix an old chainsaw, its a old norwegian one called "Jobu 81808".The problem is that it doesnt give a spark. I have tried 2 different spark plugs, ive cleaned the contacts between the flywheel and the stator. I have tested the sparkplug cable, and i have cleaned every surface that is supposed to be connected to each other. While disassembling and assembling the saw numerous times, i got lucky and it sparked 5-6 times, but no more luck after that.
I cant find any manuals for this saw eather, if you search it you will see only links to museums, haha.

Under you will se a image of how everything is wired, i might also have connected the wires wrong, but this is how it was connected when i first took it apart.

Huge thanks to everyone that replies :)
http://www.acresinternet.com/cscc.n...e8f991c897c75cf988256afc00145e97?OpenDocument
Attached is an ipl and pamphlet
 

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95custmz

95custmz

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I think HarleyT is leading you in the right direction. Usually (9 out of 10), a no spark condition is your condenser and not the coil. Good luck trying to find one. Maybe, there is one that would work, that is more commonly found on a different branded saw.
 
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