I have a Lycoming with about 50 hours on it that is behaving very badly.
It is cyclical roughness, happening every few minutes. It begins with roughness, followed by lower RPM's, higher EGT's (all) and a feeling as if it is self leaning! Fuel flow goes down by 2-4 GPH too (11+ down to 7 or 8 and EGT's rising to Peak). A few seconds (20-30) and it cures itself. Then in a few moments, it all begins again.
Isolating the mag does not improve or make it run worse or better. Same for the one Lightspeed II/Hall effect I am running. Feels like the engine is about to give up, then it takes a breath and goes on normally for a few minutes. It will run hard and even overspin the CATO prop (it's underpitched right now), then runs very poorly... like I need to find a place to land. Goes from 2750 down to 2450, and then, slowly, back up again. Scary!
Because if "feels" like a fuel issue, I traced everything in the (new) AFP 150 for loose fittings or fouled filters.... no joy. Cleaned everything and tightened fuel fittings and no change in the way it runs. Takes a few minutes on the way to altitude before it starts in, then never corrects. Same issues regardless of altitude or RPM. Could the mag be working intermittently? Hall Effect? If so, you would think isolating them would make it quit altogether, but it doesn't change anything except the EGT's go way up, and then I get nervous and switch back to both.
Any thoughts you may have are much appreciated.
Ron
RV-4
It is cyclical roughness, happening every few minutes. It begins with roughness, followed by lower RPM's, higher EGT's (all) and a feeling as if it is self leaning! Fuel flow goes down by 2-4 GPH too (11+ down to 7 or 8 and EGT's rising to Peak). A few seconds (20-30) and it cures itself. Then in a few moments, it all begins again.
Isolating the mag does not improve or make it run worse or better. Same for the one Lightspeed II/Hall effect I am running. Feels like the engine is about to give up, then it takes a breath and goes on normally for a few minutes. It will run hard and even overspin the CATO prop (it's underpitched right now), then runs very poorly... like I need to find a place to land. Goes from 2750 down to 2450, and then, slowly, back up again. Scary!
Because if "feels" like a fuel issue, I traced everything in the (new) AFP 150 for loose fittings or fouled filters.... no joy. Cleaned everything and tightened fuel fittings and no change in the way it runs. Takes a few minutes on the way to altitude before it starts in, then never corrects. Same issues regardless of altitude or RPM. Could the mag be working intermittently? Hall Effect? If so, you would think isolating them would make it quit altogether, but it doesn't change anything except the EGT's go way up, and then I get nervous and switch back to both.
Any thoughts you may have are much appreciated.
Ron
RV-4