Chasing down a hot mag issue. 62 M20C, 0-360-A1D (I think) w slick magnetos ~250 hours on them.
The mags check out fine during initial run up, both give me about 100rpm drop. Issue is during shutdown mag check or midday run up, after fueling up or something. When on L I get 100 rpm drop, R 0 rpm drop, OFF engine continues to run. So this issue only presents itself when the engine has been running for a period of time then goes away during a cold start and initial run up until warm again.
So to me, instantly, I’m thinking p-lead. Pull off the cowls and check the L p-lead and find nothing out of the ordinary. Same for the R p-lead. Hmmm?? They’re old but really for the most part seem fine.
I do a continuity check from frame(Gnd) to L p-lead stud on mag. I get continuity in OFF and R. Which is how it should work. And how Id expect it to work, at least in my case, since during initial run up everything seems fine. So I’m guessing the switch is fine (Bendix w the AD).
Anyone experience similar or have some pointers? I’d rather not toss parts at this thing. Not sure what stone to turn. P-Leads seem fine, switch seems fine, mags are 250 hours old.
The mags check out fine during initial run up, both give me about 100rpm drop. Issue is during shutdown mag check or midday run up, after fueling up or something. When on L I get 100 rpm drop, R 0 rpm drop, OFF engine continues to run. So this issue only presents itself when the engine has been running for a period of time then goes away during a cold start and initial run up until warm again.
So to me, instantly, I’m thinking p-lead. Pull off the cowls and check the L p-lead and find nothing out of the ordinary. Same for the R p-lead. Hmmm?? They’re old but really for the most part seem fine.
I do a continuity check from frame(Gnd) to L p-lead stud on mag. I get continuity in OFF and R. Which is how it should work. And how Id expect it to work, at least in my case, since during initial run up everything seems fine. So I’m guessing the switch is fine (Bendix w the AD).
Anyone experience similar or have some pointers? I’d rather not toss parts at this thing. Not sure what stone to turn. P-Leads seem fine, switch seems fine, mags are 250 hours old.