left mag intermittent

[Darter 100]

Just went thru annual (Lycoming O-320 AB ran perfect before) now left mag check and engine quits, intermittent problem. Any suggestions ?

 

[wilkersk]

Just a wild guess, without knowing anymore about it: a faulty key switch [OFF-Left-Right-Both-Start],or a P-lead pinched somewhere causing intermittent short.

 

[bradg33]

When was the last 500hr inspection of the mag? Have you tried disconnecting the P-lead all together to test for a shorted p-lead?

 

[Dan Thomas]

Best bet is a mag that needs work. Less likely is that the mechanic left the P-lead terminal touching the mag casting.

 

[Doug Reid]

If mag ran fine before annual, look for shorted p-lead like suggested above.,

 

[Darter 100]

If mag ran fine before annual, look for shorted p-lead like suggested above.,

yup exactly what it was shorted to ground shield. mecinik replaced all good thanks

 

[NordicDave]

Disconnect the p-Lead and test for continuity with an OHM meter between ground and the P-Lead. It should be an open circuit. You may need a mechanic for this next test. remove all the plugs from the engine. Clock the prop with a hand on the mag and feel for impulse coupler vibration. check both if they vibrate at the same time. Also with a piston at TDC, measure the ground to plug wire and see if the points are closing and opening as the propped is moved slightly to see the points circuit working.

This confirm if the p-leads are good and the points are working as desired.