qt50 electrics

Matt Freeman /
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I apologize for the length of the following post, but your endurance and suggestions would be most appreciated.

Problem: No Spark

Background:

I currently have two QT50's, both 1980. The blue one runs great... the red one does not. When I picked up the red one last summer, it ran well for about 30 minutes. Then it started misfiring and eventually, would produce a spark only for one or two of the cycles per kick start. If it ever did startup, it could only run for a few seconds before it lost its spark and died.

Since then I have swapped out about every electrical component from red to blue to see what is broken. Its not the CDI or the coil. I ran resistance tests on the stator and of the four circuits, three of them are a little outside of the nominal range. With this in mind I have been looking for a new stator ever since.

Present Day:

Last night after about a month or two of sitting, I decided to give it another shot. I reattach the stator and other assorted electronics and low and behold it starts up on the center stand and runs like a charm.

Now it gets weird. I want to turn it off so I can put on a jacket and take it around the block, the thumb switch is broken so I turn off the ignition but nothing happens and it keeps on running. At a loss for what to do, I pull the cap off the plug and it turns off (go figure).

Five minutes later I come back with a jacket and shoes, reattach the spark plug and kick it for the next 5 minutes. Nothing happens. I remove the plug and it seems to have gone back to its old ways of not sparking 95% of the time.

Thoughts:

I was convinced that it was the stator till last night. I would like to get an impact driver and swap stators to confirm or reject this hypothesis. Since it did run well for a few minutes last night though, I'm not so sure any more.

Not turning off seems to point to a problem maybe in the wiring of the ignition. I pulled it out last night and tested every combination of the five wires I could think of and the only change that I saw was between the red and orange wire which connect after you turn the key. All other wires seem to be unlinked in both positions.

Could it be a grounding problem. The fact that it does run for a while and then start to act up almost seems like there could be a charge accumulation in the system somewhere, but where.

Please:

Send me any ideas or suggestions... I'm coming to my wits end...

Thanks in advance.

-Matt

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