- Joined
- Nov 17, 2018
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I thought that I would run this by the group to see if anyone has any suggestions. 1981 Piper Archer 0360 A4M 90 hours SMOH. Last Sunday climbing out through a thick overcast layer, OAT around 55 degrees, the engine surged at least three times in fairly rapid sucession. Thinking that it may be carburetor ice, I pulled on the heat, and the surging stopped, but I was not sure if it was the heat, or the fact we were coming out of the overcast. We flew an hour and a half to our destination, and it ran fine. When we left our destination for the return trip, around 75 degrees, on climb out it surged again at least three times. Ice again? It ran fine on the return trip. This last Friday I was scheduled to take the plane to the Avionics Shop about 35 miles from here. On run up the plane ran very rough. Thinking that it may be a partially fouled plug, I leaned it at full power several times but it did not help. I had our local mechanic sit in the plane and watch, and his thought was a fouled plug, or sticking valve. So he pulled all of the plugs, a little sooty, but not fouled, cleaned gapped and tested. Did a compression check and that was fine. He recomended that I put some Marvel oil in the fuel and oil and run it. So Saturday I did, it was rough on climb out, but then smoothed out, and ran good for the next 45 minutes. I thought Hallelujah! This evening I went back down to fly it and make sure we were good to go. Run up smooth, but rough on climb out again at full throttle, full rich. Made several laps around the patch, and discovered that at full rich it ran rough, 2490 RPM"s, 18.5 gph per the JPI 930. I have never seen that before. Still full throttle, leaned back, it ran smooth, 15.5 gph, 2670 RPM's. EGTs and CHTs stayed even either way. What do you think?
