BDPetersen Posted 5 hours ago Report Posted 5 hours ago Not a Mooney, but maybe interesting for general knowledge. While troubleshooting hot start issue with my son’s Extra 300 we discovered the mags had been timed to 25 instead of 20 per the data plate. Waiting to see if that helped, meanwhile was interested to learn that both mags had impulse couplings. I guess that’s a thing with fuel injection as opposed to the left mag only on the carbureted engines I relate to.? But even more interesting was to discover each mag fires both top and bottom plugs on its side of the engine, left serving even # cylinders, right doing the odd ones. I’ve never seen that and I’m not sure how to confirm it. I suppose the Lycoming manual may address that. Any thoughts?
Hank Posted 4 hours ago Report Posted 4 hours ago The firing order is weird. When I lost a mag in flight, I'm really glad that all four cylinders were still running, not just two of them. Only lost a little speed, reached my destination and called the local A&P.
EricJ Posted 4 hours ago Report Posted 4 hours ago 58 minutes ago, BDPetersen said: Not a Mooney, but maybe interesting for general knowledge. While troubleshooting hot start issue with my son’s Extra 300 we discovered the mags had been timed to 25 instead of 20 per the data plate. Waiting to see if that helped, meanwhile was interested to learn that both mags had impulse couplings. I guess that’s a thing with fuel injection as opposed to the left mag only on the carbureted engines I relate to.? Some do that on experimentals just to get better starts. It's not a bad idea other than adding a little complexity. I don't think it has much to do with whether it's fuel injected or carbureted. 58 minutes ago, BDPetersen said: But even more interesting was to discover each mag fires both top and bottom plugs on its side of the engine, left serving even # cylinders, right doing the odd ones. I’ve never seen that and I’m not sure how to confirm it. I suppose the Lycoming manual may address that. Any thoughts? That sounds very unusual. It's fairly common to have one mag fire the top on one side and the bottom on the other, but, as Hank mentioned, you'd lose redundancy if a mag fired only one side (which sounds like it'd take a special mag, anyway).
N201MKTurbo Posted 4 hours ago Report Posted 4 hours ago 1 hour ago, BDPetersen said: Not a Mooney, but maybe interesting for general knowledge. While troubleshooting hot start issue with my son’s Extra 300 we discovered the mags had been timed to 25 instead of 20 per the data plate. Waiting to see if that helped, meanwhile was interested to learn that both mags had impulse couplings. I guess that’s a thing with fuel injection as opposed to the left mag only on the carbureted engines I relate to.? But even more interesting was to discover each mag fires both top and bottom plugs on its side of the engine, left serving even # cylinders, right doing the odd ones. I’ve never seen that and I’m not sure how to confirm it. I suppose the Lycoming manual may address that. Any thoughts? Are you sure the harness was installed correctly?
BDPetersen Posted 3 hours ago Author Report Posted 3 hours ago Ok, this was a ridiculous post and I apologize. It’s obvious I misread the plug wires or it would not have run on one mag (3 cylinders). Even with my newly cataract free eyes, I can make mistakes. Good news is we had 2 successful hot starts. I’m reminded of a captain I flew with once who made a lengthy p/a to the passengers but mistakenly picked up the wrong mic and broadcast it on comm one. Before he finished he realized what he was doing and continued by saying to his audience of airline pilots “ I’m just going to hang up now and take off my headset, so make all the comments you want, I’m not listening “ Ya’all have a great day! 1 3
Ragsf15e Posted 47 minutes ago Report Posted 47 minutes ago 3 hours ago, BDPetersen said: Ok, this was a ridiculous post and I apologize. It’s obvious I misread the plug wires or it would not have run on one mag (3 cylinders). Even with my newly cataract free eyes, I can make mistakes. Good news is we had 2 successful hot starts. I’m reminded of a captain I flew with once who made a lengthy p/a to the passengers but mistakenly picked up the wrong mic and broadcast it on comm one. Before he finished he realized what he was doing and continued by saying to his audience of airline pilots “ I’m just going to hang up now and take off my headset, so make all the comments you want, I’m not listening “ Ya’all have a great day! I was surprised to learn that my m20k has two impulse mags and is wired to start on both mags. My F model with an io-360 was injected as well but only used one mag for starting. Your whole post wasn’t crazy, just a tiny bit!
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