Author Topic: magneto problem  (Read 2456 times)

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Offline Longshot-EZ

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magneto problem
« on: November 02, 2016, 01:51:00 PM »
I have been having very hard, almost impossible hot starts this summer.  I had an ANP time my mags and he said they were off by about 6 degrees.  unfortunately that didnt fix the hard hot starts.  During my recent panel upgrade I was worried to see a fairly melted wire on the starter switch.  it was used as the jumper that grounds the right mag when you start so the Impulse coupling can do its thing.  I thought this must be the reason for my problems so I replaced the wire and took out the trusty AM meter to check function.  When I switch to either L or R I get continuity through both P wires which means when you ground one you ground both mags.  If I switch to BOTH the continuity is gone meaning neither mag is connected to the ground which is correct.  This lead me to believe that the P Leads where somewhere shorted together so I ran new ones just open not fished through the firewall.  Hooked them up, ran my meter tests and got the same results.  Tested the starter switch with no leads connected and it is working as it should.  so, with the wires disconnected from any switch, I tested and got continuity through the P Leads which means they are sharing a connection through the mags? 

That would have to be the engine right?  If that's the case it means that the mags are grounded to the engine which would keep them from firing.

On the advice of Beagle I hooked up just two toggle switches just to see, but got the same results with the meter.

I hope what I'm saying makes some sense.  I've been trying to find out if there is a way to test the mags on the plane to see if they are grounded out but cant find any ideas.

I get the engine turning over but no start at all now.  I'm stuck and would appreciate any advice that isn't throwing parts at it cause that's what I'll have to do soon.
LONG-EZ N141  This was the plane I wanted when I started flying in '86'

Offline flyingwaldo

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Re: magneto problem
« Reply #1 on: November 02, 2016, 02:15:04 PM »
Being very electrically challenged I had the same problem trying to check my mag wiring.  Turns out, and hopefully a smarter person will explain it to you, it will always show continuity and you can't test it that way.  Good luck.

Offline Longshot-EZ

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Re: magneto problem
« Reply #2 on: November 02, 2016, 03:39:05 PM »
Other than feeling foolish for wasting all the time trying to figure it out,  I hope you're right and it is all just pilot error. LOL
LONG-EZ N141  This was the plane I wanted when I started flying in '86'

Offline flyingwaldo

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Re: magneto problem
« Reply #3 on: November 05, 2016, 07:37:35 PM »
http://www.aircraftmagnetoservice.net/


Call the fellow at Aircraft Magneto Service in Washington.  Really great guy will be very helpful and educate you, as he did me.  They may have moved.






« Last Edit: November 05, 2016, 08:02:21 PM by flyingwaldo »