Hello. I would be very appreciative if someone could point me in the right direction for diagnosing an issue that just popped up.
I purchased an RV-6A 12 months ago and it came with dual pmags. I've flown it 50+ hours with no issue. During run up today I noticed that the RPM reading on my engine monitor was sporadically dropping to 0, every few seconds or so while on both magnetos. The engine monitor is quite old (it's an RMI umonitor) and so my initial thought was that it was failing. However, there are a few things that then made me think it's one of the pmags instead:
1. the RPM reading issue seems to only happen on the right mag or on both, not while on the left mag.
2. the engine also sounds like it's running slightly slower on the right mag (it's not running rough, just at a slightly lower power setting compared to the left mag).
3. The right mag is the older of the 2 pmags (7 years / 600 hours old). The left was replaced several years later.
4. I read in the umonitor installation guide that a failing mag could potentially cause failures with the umonitor.
So is it probable that the pmag is starting to fail? If so, what's a good way to test for that? I looked in the troubleshooting guide on the emagair website but none of those tests seem to apply to this situation.
Or are there other causes I should be considering instead? Loose wiring or something else?
Thank you very much.
I purchased an RV-6A 12 months ago and it came with dual pmags. I've flown it 50+ hours with no issue. During run up today I noticed that the RPM reading on my engine monitor was sporadically dropping to 0, every few seconds or so while on both magnetos. The engine monitor is quite old (it's an RMI umonitor) and so my initial thought was that it was failing. However, there are a few things that then made me think it's one of the pmags instead:
1. the RPM reading issue seems to only happen on the right mag or on both, not while on the left mag.
2. the engine also sounds like it's running slightly slower on the right mag (it's not running rough, just at a slightly lower power setting compared to the left mag).
3. The right mag is the older of the 2 pmags (7 years / 600 hours old). The left was replaced several years later.
4. I read in the umonitor installation guide that a failing mag could potentially cause failures with the umonitor.
So is it probable that the pmag is starting to fail? If so, what's a good way to test for that? I looked in the troubleshooting guide on the emagair website but none of those tests seem to apply to this situation.
Or are there other causes I should be considering instead? Loose wiring or something else?
Thank you very much.