Well, I know my idle mixture is too lean, because I'm seeing no rise in RPM on shut down. Unscrewing the mixture screw doesn't help, so I suspect there's an issue with the mixture circuit. The the carb is headed to the shop to have this checked out.
The company who sells my electronic ignition system, Electroair, thinks I'm running too lean overall, this based on a large drop of 150-175 RPM at run up. The drop on the single left mag is only 50.
I've checked for an induction leak. . . no joy.
I've changed the plug wires. . . no joy.
I've swapped the upper/lower spark plugs. . . no joy.
I've checked the EIS timing. . . perfect.
So, I assumed there may be an issue with the EIS itself, perhaps a bad coil. They don't think so, especially since my plugs are so clean. They're saying that lean mixture roughness will be apparent on the EIS but not the mag because of the higher efficiency and longer spark duration of the EIS.
I Figure since I'm sending the carb to the shop to investigate the idle circuit leanness, I might as well wait and see if something else shows itself.
The carb shop tells me that a number of their customers have had their overall mixture richened by drilling out the main jet ten-thousands. I'm not sure mine needs this, but I'm pretty sure its not running overly rich either. My plugs appear pretty light gray. . not sure if it's light enough to indicate an over-lean condition, but I'm going to get the carb shop to look at it. I'm not really seeing excessively high EGT, but I've only got about 10 hours on the airplane, and I always aggressively lean in flight, so I can't say for sure. Oil temps could probably be higher. I run near the bottom of the green.
So what's the harm of having the carb richened a bit. Has anyone done this? I figure I can still use the mixture knob to lean where I need to be, but is there any downside to doing this?
Thanks!
The company who sells my electronic ignition system, Electroair, thinks I'm running too lean overall, this based on a large drop of 150-175 RPM at run up. The drop on the single left mag is only 50.
I've checked for an induction leak. . . no joy.
I've changed the plug wires. . . no joy.
I've swapped the upper/lower spark plugs. . . no joy.
I've checked the EIS timing. . . perfect.
So, I assumed there may be an issue with the EIS itself, perhaps a bad coil. They don't think so, especially since my plugs are so clean. They're saying that lean mixture roughness will be apparent on the EIS but not the mag because of the higher efficiency and longer spark duration of the EIS.
I Figure since I'm sending the carb to the shop to investigate the idle circuit leanness, I might as well wait and see if something else shows itself.
The carb shop tells me that a number of their customers have had their overall mixture richened by drilling out the main jet ten-thousands. I'm not sure mine needs this, but I'm pretty sure its not running overly rich either. My plugs appear pretty light gray. . not sure if it's light enough to indicate an over-lean condition, but I'm going to get the carb shop to look at it. I'm not really seeing excessively high EGT, but I've only got about 10 hours on the airplane, and I always aggressively lean in flight, so I can't say for sure. Oil temps could probably be higher. I run near the bottom of the green.
So what's the harm of having the carb richened a bit. Has anyone done this? I figure I can still use the mixture knob to lean where I need to be, but is there any downside to doing this?
Thanks!