O-360 with dual EFII ignition with autowires/plugs, rebuilt 2009, first engine start Sept 2014 and 96 hours without any rough running etc last year. 10 hours since condition inspection, during the condition inspection I sent the Carb to Marvel Schebler and they enriched it slightly and replaced the bowl. First 6 hours after the condition everything ran as it should. I did get fuel at the airport before the issue, but my tanks sumped clean in the pre-flight and I had them double check their truck this morning.
I flew about 2.5 hours yesterday morning without any issues, 3rd leg of the day I slightly leaned in the climb about 120-150 ROP and leveled off at 13.5. I accelerated to cruise speed, CHT's were all 380 or less I left full throttle in and made a big pull to LOP (I only do LOP below 65% power). About minutes after setting 20-80 LOP the engine ran rough like it was ingesting water or had bad carb ice (too instantaneous for carb ice). It felt like a LONG time, data shows just over a minute of rough running. I swapped fuel tanks, turned on the boost pump with no change. When I went full rich with the mixture it bogged the engine more and I leaned it about where I thought it should be it eventually smoothed out.
I pulled the SD cards and looked at the data this morning, about 250 RPM and 10 knts IAS loss in the minute. Fuel flow went from 7.8 to 9.6. EGTS were all 1310-1330 before and dropped to 895-1070 with #2 being the lowest. It was long enough that CHT's even dropped around 30 degrees.
After it smoothed out I tried ROP and LOP and both ran fine, after running LOP for about 30 minutes I started descending. I left the throttle full in and mixture at 20-80 degrees LOP. At about 13.2 the engine ran rough again for about a minute with the same drop in EGT's/CHT's/RPM/Airspeed. Small mixture adjustments as well as large mixture adjustments didn't seem to make a difference. After it smoothed out it ran flawlessly through several
level offs and different mixture/power settings for the last 40 minutes of the flight.
After startup on the ramp for my last leg I had the same stumbling as I advanced the throttle through 1200 RPM to taxi up-hill. It wasn't very noticable, I felt it more than heard it. I was able to hear it after removing my headset. Switching ignitions behaved as I would expect with a slight loss of RPM but still rough running. I aggressively leaned it out and it smoothed out after about 45 seconds. I did an extended runup and everything ran fine, after a cautious takeoff the hour flight back home was uneventful.
The data on the ground showed the #2 EGT during the rough running was 500 degrees while the other 3 cylinders were 1250's.
Looking back over the data for the previous flights of the morning when everything ran normal. During a full power, Full rich climb #2 is my richest cylinder with EGT's 180-200 degrees cooler than the other cylinders. When LOP in cruise it is within 10-15 degrees of the other cylinders.
I'm looking for things to check when I pull the cowl, ideas?
Thanks,
Andy
I flew about 2.5 hours yesterday morning without any issues, 3rd leg of the day I slightly leaned in the climb about 120-150 ROP and leveled off at 13.5. I accelerated to cruise speed, CHT's were all 380 or less I left full throttle in and made a big pull to LOP (I only do LOP below 65% power). About minutes after setting 20-80 LOP the engine ran rough like it was ingesting water or had bad carb ice (too instantaneous for carb ice). It felt like a LONG time, data shows just over a minute of rough running. I swapped fuel tanks, turned on the boost pump with no change. When I went full rich with the mixture it bogged the engine more and I leaned it about where I thought it should be it eventually smoothed out.
I pulled the SD cards and looked at the data this morning, about 250 RPM and 10 knts IAS loss in the minute. Fuel flow went from 7.8 to 9.6. EGTS were all 1310-1330 before and dropped to 895-1070 with #2 being the lowest. It was long enough that CHT's even dropped around 30 degrees.
After it smoothed out I tried ROP and LOP and both ran fine, after running LOP for about 30 minutes I started descending. I left the throttle full in and mixture at 20-80 degrees LOP. At about 13.2 the engine ran rough again for about a minute with the same drop in EGT's/CHT's/RPM/Airspeed. Small mixture adjustments as well as large mixture adjustments didn't seem to make a difference. After it smoothed out it ran flawlessly through several
level offs and different mixture/power settings for the last 40 minutes of the flight.
After startup on the ramp for my last leg I had the same stumbling as I advanced the throttle through 1200 RPM to taxi up-hill. It wasn't very noticable, I felt it more than heard it. I was able to hear it after removing my headset. Switching ignitions behaved as I would expect with a slight loss of RPM but still rough running. I aggressively leaned it out and it smoothed out after about 45 seconds. I did an extended runup and everything ran fine, after a cautious takeoff the hour flight back home was uneventful.
The data on the ground showed the #2 EGT during the rough running was 500 degrees while the other 3 cylinders were 1250's.
Looking back over the data for the previous flights of the morning when everything ran normal. During a full power, Full rich climb #2 is my richest cylinder with EGT's 180-200 degrees cooler than the other cylinders. When LOP in cruise it is within 10-15 degrees of the other cylinders.
I'm looking for things to check when I pull the cowl, ideas?
Thanks,
Andy