Mag Switch Malfunction

[zipperdu]

Hey folks,
I found I had a "sweet spot" on my mag switch that wasn't very sweet! It's the standard AAF Type A7 Switch thats used on most of these airplanes. I found if you move the switch to the off detent and push just slightly more, it aint off!!

Being a mechanic, I've had run-ins with bad mag switches before, it's not unheard of....

If your out there flipping that prop, you gotta know it could fire at any time!!

Please be careful.

Jon NC81488 7ac

[Paul Agaliotis]

John,
If it's a B&S switch there is an AD for this very issue.
Paul

[zipperdu]

Hi Paul,
There are two ADs, 53-26-01 and 50-04-01 both applicable to Briggs and Stratton Magneto Switches. The model numbers are B-5 and A-8 . As I read it the A7 switch in not applicable, however the failure mode is exactly like the 50-04-01.
Thanks for the reply.

Jon

[Paul Agaliotis]

Jon,
The AD you need is 50-04-01. I don't know of B&S making an A-8 switch, I have never run across one. I guess we could ask the FAA for clarification.......................................................................... no, I'm just kidding!
Paul

[zipperdu]

yeah,.............roger that!
Jon

[brink]

This post is about 8 years old, but I was trying to run down AD Notes on a Briggs and Stratton BS -49 I think a letter follows that number, but I can’t make it out even under magnification. It might be an (M).Anyway the Switch had about 4 coats of Black Paint,and the Lettering was almost gone on the face of this switch. It appears to be exactly like a -7 or-8 military style Magneto switch,fits in the Aeronca 7-AC Engine control panel perfectly. And it works, I tightened up the rear panel it was lose, just bent the 4 ears in and down, nice and tight now. Because it worked,I elected not take the switch apart. The only real difference is the attach electrical hardware is standard fine thread screws with lock washers, not fine AN internal lock nuts. Only one screw in the Ground lug was in the Switch,the Magneto Screws were missing. I had a set of replacement Screws and washers with lock washers, I stripped the face of the Switch with Paint Stripper, and got read of the Corrosion with Naval ?Jelly. Who ever painted the Switch painted it right over the Corrision. I can’t find any AD Notes on this switch, so I think Its Clean, quite possibly manufactured prior to the AD note Program. This Switch is Old! But very well built, with thicker metal in its construction, when I stripped the paint I found lettered illustrations. OFF, Mag 1,Mag2, Both. What is this,Fairchild,Lockheed,
Stinson! It’s got to be in the 30s maybe 20s, I’ve never seen one,quite like this!
AD