Author Topic: Jonsered 80/801/90 ignition system problems  (Read 405 times)

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Offline awol

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Jonsered 80/801/90 ignition system problems
« on: December 12, 2014, 10:49:35 pm »
   After building an engine and 801 saw out of a pile of parts, I am having much difficulty getting it to fire. Both coils, condensor, and breaker points test good, but only provide a very weak and intermittent spark. I have another 801, known to be a good runner, so I pulled the unit off it and installed in the new one with the same results. What is the cure for this problem, or maybe the question should be, what is the problem?? There is no adjustment for coil to flywheel air gap, the points are set at .020, and the unit is set in the center of it's travel. Any help or pointers would be greatly appreciated, this is the distribution system of this type I have worked on.
New ported Husqvarna and Jonsered saws. Woods porting of saws by appointment.

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Offline 660magnum

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Re: Jonsered 80/801/90 ignition system problems
« Reply #1 on: December 12, 2014, 10:55:32 pm »
Did you check the flywheel for magnetism and compare it with some good running saws?

The old style condensers often go bad
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Offline awol

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Re: Jonsered 80/801/90 ignition system problems
« Reply #2 on: December 12, 2014, 11:19:14 pm »
   The magnet feels strong, I did not swap with another saw, will compare them and try that.
New ported Husqvarna and Jonsered saws. Woods porting of saws by appointment.

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Offline awol

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Re: Jonsered 80/801/90 ignition system problems
« Reply #3 on: December 15, 2014, 10:58:43 am »
   One set of magnets felt stronger than the other, so I installed that flywheel and had a spark that was somewhat stronger, but still would not run. Because of the flywheel making a difference, I tried moving the coil closer to the flywheel and the spark disappeared. Moved the coil away from the flywheel as far as it would go, and now have good strong spark. I had to file down the step on the points base to be able to move it around.
New ported Husqvarna and Jonsered saws. Woods porting of saws by appointment.

doittheoldway@gmail.com  417-259-0248

Offline 660magnum

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Re: Jonsered 80/801/90 ignition system problems
« Reply #4 on: December 15, 2014, 11:21:06 am »
Lets hope the timing advance didn't change?
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Offline awol

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Re: Jonsered 80/801/90 ignition system problems
« Reply #5 on: December 15, 2014, 03:53:11 pm »
   It may have changed slightly, but the breaker plate has plenty of room for adjustment in both directions. I also found out after running it for a but today that the crank is bent slightly. That may explain why moving the coil away from the flywheel made a difference.
New ported Husqvarna and Jonsered saws. Woods porting of saws by appointment.

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Offline 660magnum

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Re: Jonsered 80/801/90 ignition system problems
« Reply #6 on: December 15, 2014, 05:01:17 pm »
Normally cranks don't actually bend. Sounds strange???

What happens is the counter weights twist at the crank pin where the two halves are pressed together.

If you don't have another crank, the are people who can re-align your crank for you but you will need to remove it from the crankcase and send it off.

Let us know?

Congrats on getting it running
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Offline 660magnum

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Re: Jonsered 80/801/90 ignition system problems
« Reply #7 on: December 15, 2014, 05:05:15 pm »
This happened because of a sudden lock up stoppage of the saw either on the clutch side or the flywheel side.  - - more likely a chain stoppage?
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