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Slick magneto timing

hcccs

Well Known Member
I'm trying to time my 4370/1 Slick magnetos. These have been running on the engine before I purchased it so I'm confident they are OK. I use a timing device with two LEDs and when the points open the lights come on but the lights are out all the time which seems to indicate that the points never open. I disonnected the ignition switch wire from one P-lead and tried it but it was the same. I have timed Bendix magnetos many times and this should not be any different. Am I overlooking something here?
 
What Bob said... Is there a known good battery in the box? Mine has red/green LEDs so I know if it has power.

Don
 
What Bob said... Is there a known good battery in the box? Mine has red/green LEDs so I know if it has power.

Don

My box runs off the aircraft battery and it's good. I disconnected the P-lead of one magneto and connected directly to it and there is no change. Can it be anything else than a worn cam in the magneto?
 
Couple of ideas??

I disconnected the P-lead of one magneto and connected directly to it and there is no change. Can it be anything else than a worn cam in the magneto?

These come to mind-----

Bad wire from the external connection to the points/condenser.

Bad insulator at the external connection.
 
I am curious. You say your mag timing light has two LEDs.

Mine does too. Would it be the following unit, like mine?

12-16901.jpg


If so, it has an internal 9V battery. Unit will not work with low battery.
 
My box runs off the aircraft battery and it's good. I disconnected the P-lead of one magneto and connected directly to it and there is no change. Can it be anything else than a worn cam in the magneto?

Faulty box. I borrowed another one and now all is OK.
 
I am curious. You say your mag timing light has two LEDs.

Mine does too. Would it be the following unit, like mine?

12-16901.jpg


If so, it has an internal 9V battery. Unit will not work with low battery.

Also, as infrequently as we use these, take the battery out so it doesn't gum up like they do when left long periods....my A&P turned me on to that gem when I bought a new one.
 
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