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Ignition Switch and Mags

pa38112

Well Known Member
I have found that my O-360-A1A usually starts As soon as I release the starter switch. If I keep cranking it does not typically start. I have a standard Vans ignition keyed switch. Does this sound like a bad contact position in the switch?
 
Does this sound like a bad contact position in the switch?

Is this a new installation, if so, sounds more like you have it wired wrong.

If this is something new on a plane that has been flying and starting normally, it could be a bad contact or something else in the wiring.
 
Is this a new installation, if so, sounds more like you have it wired wrong.

If this is something new on a plane that has been flying and starting normally, it could be a bad contact or something else in the wiring.

Perhaps L and R mag wires swapped if there is only one impulse mag?
 
It could also indicate a weak impulse mag. Normally the non-impulse mag is disabled in the start position. When you release the switch the non-impulse mag is on.

This is a pretty common indication of a weak mag. Been there, Done that, Got the t-shirt. Now I have 2 impulse mags. Turn both switches on, hit the start button, and go!
 
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Had the same symptoms. Difficulty in starting became worse. Mag check was ok, when I could get it started. Checked fuel flow, spark plugs, mag timing, ignition switch, and mag grounding. Turned out to be a bad left mag. Overhaul shop tested it both hot and cold. Coil was bad and points were not set properly. I had the mag rebuilt and solved the starting problem. Mag only had about 310 hours.

Check all the easy stuff first before pulling the mag. Mag overhaul will cost $$$.
 
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