Slick 4370 Non impulse mag

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brian metzger

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Aug 11, 2025, 9:18:05 PMAug 11
to RV Squadron Falcon
Hey all, I’m troubleshooting a bad mag I believe. My right one. Anyone have an old one that may be laying around as a spare (that was working well last time you used it!) I could test to determine for sure my mag is bad before I replace or go with another ignition system?

4370 non impulse, Left rotation.

Thanks,

Meat

JBMcClanahan

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Aug 12, 2025, 6:49:29 AMAug 12
to brian metzger, FalconRV-List
Hey Brian - I attended a forum by Champion on Slick Mags last year.  I thought you might find what they said helpful regarding Slick Mag troubles -

1.  First, check logs for time in service.  Slick mags need service at 500 hours/12 years (bearing grease dries out with time).  Going beyond that is asking for trouble.

2.  Mags are very reliable up to the 500 hour point.  So if you think you have a mag problem and you're under 500 hours, check everything else first - plugs, harness, etc.

3.  Harnesses don't last forever.  They break down internally.  They may look good on the outside but need to be thrown away at engine overhaul if not sooner.  I have a harness tester you can borrow.  Here's how it works -






4.  Don't use magneto noise filters on Slick Mags.  They throw off timing and cause a weak spark.

So those are some things to think about, the main one being hours/time in service...

Here's a pretty good summary on Slick 500 hour checks in Kitplanes -


I hope this helps.  Let the group know what you find..we all might learn something.

Thanks -

John McClanahan







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Kent D. Edmunds

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Aug 12, 2025, 7:51:22 AMAug 12
to JBMcClanahan, brian metzger, FalconRV-List
Based on a recent personal experience of a dual mag failure (on the ramp, thank goodness.) I would never I ran a magneto. I would absolutely insist on an overhauled magneto.  I know there are hundreds of thousands of hours run on IRANed mags however, in my case, teeth from the nylon gears broke off.  Those gears had only been inspected and not replaced.   Just over 50 hours since IRAN  Personally I can’t imagine why anyone would think that’s a good idea.

Kent  Edmunds


vic syracuse

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Aug 12, 2025, 7:53:13 AMAug 12
to Kent D. Edmunds, JBMcClanahan, brian metzger, FalconRV-List
I always replaced those gears in every mag I overhauled. But now the prices of the parts are almost the same as an overhauled mag from Spruce, so I do that. 

Sent from Gmail Mobile


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