M

markscogg

Well Known Member
There is a "P Lead" wire that looks like it spliced and also connected to the mag ground screw on both mags. Hard to be sure without cutting open the heat srink.
Does anyone know what it is for? I want to connect a Slick Start, which uses three wires, power from solenoid, one to the "P Lead" and one to the mag ground screw. Looks like they are jumpered, so that won't work?
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The wire that is going to the mag case is a shield ground. The P Lead should be made of shielded wire for radio noise suppression. The other end of the shield should not be connected, however I have seen aircraft that had the ground terminal of the mag switch connected to the cockpit side of the shield braid instead of a ground under the instrument panel.
 
FYI, from the looks of the picture, the lock washer under the case ground screw looks entirely too large to be much good. A -08 washer would be more appropriate in my estimation.
 
Slick Start wiring?

Mike H said:
The wire that is going to the mag case is a shield ground. The P Lead should be made of shielded wire for radio noise suppression. The other end of the shield should not be connected, however I have seen aircraft that had the ground terminal of the mag switch connected to the cockpit side of the shield braid instead of a ground under the instrument panel.
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So I can hook up the Slick Start as per instructions, since this is just a shield ground?
Does the Slick Start wiring need to be shielded, since it is only hot when the starter is engaged?
(Putting on a used unit, no harness included.)
Thanks,
Mark
 
I have never installed a slick start unit. Does the documentation specify which type of wire to use?
 
Slick Start

When installing the slick start on a slick 4300 series impulse coupled magneto(one slick start per mag) the slick start wire piggy-backs on the normal P-lead connection. I would use shielded wire and ground the shield to the same ground screw as the p-lead shield, with the correct star washer of course...To get the instructions download a copy of Slick Service Letter SL2-96. Good Luck, Russ
 
Lots of certified aircraft do not use the shield as a ground for the mag switch. Then again some do. PA-28 aircraft 67' and prior use the shield as the switch ground. 68' and later models have a ground wire from the ground terminal of the switch connected to the lower left instrument panel area. I prefer the latter installation because if the shield is the only ground path, then when it breaks you will have a hot mag.
 
I installed a new Slick Start, and it came with multi-conductor shielded wire.
I presume that's an impulse mag; if it's a retard mag then there is one more wire to hook up.
 
ground

there have been some detailed explanations in the past about why the shield should NOT be grounded at the switch. The late Paul Lipps was an advocate of NOT grounding the shield at the switch.
 
Slick Start

I have a used unit. The new unit comes with a wiring harness, so the instructions don't mention what type of wire to use.
I will use a shielded wire from the P Lead to the Slick Start, and ground the shield to the mag.
I think the other two wires can be non shielded. They are just power and ground.
Of course I will use the proper star washer.
Thanks everyone for their help.
Mark
 
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