Craftsman 143.666072

Scrubcadet10

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143.666072
Craftsman engine made by Tecumseh...
Odd spark issue... new OEM points and condenser and coil.
Point gap set at highest point to .020".
The spark will not jump a gap... only if i touch the metal spark plug connector on the end to metal and i will see a bright blue spark, but it just will not jump ANY gap.
I'm noticing that the flywheel magnets (flywheel has 2 magnets) have been reglued with a hard steel epoxy... I was wondering if they were put in the wrong order could this cause a weak spark issue, or would that result in a complete no spark issue?
Thanks!
 

slomo

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Is 0.020" gap correct? Trying to recall but the Ford 390 v8 was like 0.014". Actually you used to use a matchbook flip open cover to gap those. Magnets could be out of polarity.

slomo
 

slomo

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I would say it's magnet time. You replaced everything else right? Maybe drag a screwdriver across them and see how they are attracted or not to the driver. ??

slomo
 

tom3

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I'd sure think that if the magnets were glued in wrong the primary voltage would be weak. But are these just charging magnets inside or the actual ignition primary magnets?
 

Scrubcadet10

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they are the ignition primary magnets.... No charging system on this particular motor.
but are located under the flywheel since Tecumseh put the coil behind the flywheel
 

tom3

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Aha. Then need to check for polarity of the two magnets, plus minus 1st magnet to plus minus 2nd magnet if the magnets are actually made that way. Easy to put them back in wrong. Just use a small magnet to check them.

edit. Went out and checked a flywheel off a HH70, each magnet is full polarity, one is +, one is - so if they are about 1/2 inch apart they should work if the same as mine. I'd guess they would have been put on the same location as before so timing should be right.
 
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bertsmobile1

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It should not make any difference because this system has points & not a Hall effect chip, but try flipping the coil over.
Because this is avery old engine there is no reason to believe that the coil & flywheel are a matched set.
 

Scrubcadet10

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Aha. Then need to check for polarity of the two magnets, plus minus 1st magnet to plus minus 2nd magnet if the magnets are actually made that way. Easy to put them back in wrong. Just use a small magnet to check them.
took a magnet out there (but i have know of knowing which side of the magnet is + or -) the first flyhweel magnet to pass the plate sucked in the magnet, and the next magnet on the flywheel opposed the magnet.
It should not make any difference because this system has points & not a Hall effect chip, but try flipping the coil over.
Because this is avery old engine there is no reason to believe that the coil & flywheel are a matched set.
This engine's magneto slides over the plate, I don't really see how reversing it would change anything... heck, i may try using one of those electronic ignition modules from stens, or that Kawasaki igniter and get rid of the points..:unsure: IF that's the problem, but i really don't think so.
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