JP Dice Posted June 13, 2018 Report Posted June 13, 2018 I have a 1978 J-Model Mooney with the dual mag single drive setup. This morning I noticed the airplane was not as quick to start as typical. I taxied out to the runway and did my mag check. Left mag - good drop. Right mag - the engine would not run. I had to turn back to left mag to keep it going. First thought was some fouled plugs/carbon build up. I tried leaning it and burning it off. No luck. I had the same problem again. I taxied back to ramp. Mechanic came out (about an hour later) - airplane was very tough to start and was rough on right mag, but would at least remain running unlike before. We removed the cowling. Noticed some oil around the mag and gasket. Not sure if that is related to issue or not. Anyone have any idea what would cause this issue? Until today - there have been no starting or mag issues with the airplane. JP Dice Birmingham, AL. Quote
kortopates Posted June 13, 2018 Report Posted June 13, 2018 It's certainly related if the mag securing hardware has become loose to shift the timing and leak oil from the mag. A few have been known to literally fall off from not re-installing or re-torquing with new and proper lock washers per a Lycoming SB.Sent from my iPhone using Tapatalk 2 Quote
Bartman Posted June 13, 2018 Report Posted June 13, 2018 Shortly after I bought mine there was an engine leak. I asked the mechanic on the field to take a look and he went straight for the oil filler door and shook the magneto, which was about to fall off. That was 2007 and the plane had the PPI done at a Mooney Service Center just prior to me picking her up. I think it was right around that time the SB came out for the magneto clamps and hardware. When I first started coming to Mooneyspace there was the occasional thread about the oil leak and loose magneto. I have not seen any new threads on that in a long time. 1 Quote
Oldguy Posted June 13, 2018 Report Posted June 13, 2018 Check the logs for the last mag overhaul against the current hours on it. Mine had the same symptoms and was literally 3 hours past the o/h time. But the oil, hard starting, and changing symptoms indicate to me the mag is loose. Good job catching it on the ground! Quote
N201MKTurbo Posted June 13, 2018 Report Posted June 13, 2018 There are a couple of things that can cause your problem. One is the points have warn and are not opening. I reciently had the same problem and it turned out to be a broken distributor gear. The first thing I would do Is put a mag timer on it and see if both points are working. If they are then you need to get the mag fixed. If the points are not working then adjust the points. 1 Quote
carusoam Posted June 14, 2018 Report Posted June 14, 2018 Read up on star washers, if you are not familiar... They are the securing hardware. Onetime use type lock washers that only work exactly once... if they got reused, you might have some loose hardware related to the bolts holding the mags in place... PP thoughts only, not a mechanic... Best regards, -a- Quote
Andy95W Posted June 14, 2018 Report Posted June 14, 2018 If the attaching hardware was the cause, the left mag would also be affected. I'm leaning toward internal failure like Rich said. The oil evidence could be the result of oil contamination of the right side of the mag, which would indicate a bad seal, so again: internal failure. Quote
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