I was out to try and fly my Arrow this past weekend and shortly after I started the engine, it started sputtering pretty good with wild fluctuations in RPM (500-800 rpm to almost dieing at times) and my fuel flow gauge going wildly out of control (3 gph to 8 gph) without touching either the mixture control or throttle.
This has happened in the past and I'd just run the engine at 2000 rpm or higher for a few minutes and she ran just fine. This past weekend, the fluctuations were much more severe and at times struggled to keep the engine running even at full throttle some big sputtering was occurring. After shutting down I had a pilot friend observe from the outside and said when the boost pump was on (pre-start) he saw fuel spilling out of the over flow. Even after start up, fuel was still spilling out of the over flow (boost pump was off at this point).
Because the engine scared the crap out of me, I had my mechanic take a look at it and run it for 20 minutes today. He said my engine was one of the smoothest and best running engines he's seen. He also took off the cowling and said there are no leaks or other signs of damage or something wrong with the engine. No fuel was coming through the overflow with or without the boost pump on. He is convinced the engine is fine and that it was just really flooded and the plugs were contaminated causing the roughness. In fairness, I didn't lean out the mixture to test that theory. Still having my doubts, I called another mechanic over the phone and his response was "I feel bad for both you and the mechanic" since he understands my concern but feels for the mechanic so you can't fix what you can't replicate. He seemed like he was slightly skeptical about the mechanic number 1's opinion although he knows that mechanic and knows he has a good reputation. My (long-winded) question is to those A&P's on here................ does it sound like flooding or some other issue? I guess I can buy the flooding answer since I've had my plane in several months ago by the mechanic to take a look at the same issue that again was not able to be replicated and have flown probably 40 hours in that short time frame with no issue.
This has happened in the past and I'd just run the engine at 2000 rpm or higher for a few minutes and she ran just fine. This past weekend, the fluctuations were much more severe and at times struggled to keep the engine running even at full throttle some big sputtering was occurring. After shutting down I had a pilot friend observe from the outside and said when the boost pump was on (pre-start) he saw fuel spilling out of the over flow. Even after start up, fuel was still spilling out of the over flow (boost pump was off at this point).
Because the engine scared the crap out of me, I had my mechanic take a look at it and run it for 20 minutes today. He said my engine was one of the smoothest and best running engines he's seen. He also took off the cowling and said there are no leaks or other signs of damage or something wrong with the engine. No fuel was coming through the overflow with or without the boost pump on. He is convinced the engine is fine and that it was just really flooded and the plugs were contaminated causing the roughness. In fairness, I didn't lean out the mixture to test that theory. Still having my doubts, I called another mechanic over the phone and his response was "I feel bad for both you and the mechanic" since he understands my concern but feels for the mechanic so you can't fix what you can't replicate. He seemed like he was slightly skeptical about the mechanic number 1's opinion although he knows that mechanic and knows he has a good reputation. My (long-winded) question is to those A&P's on here................ does it sound like flooding or some other issue? I guess I can buy the flooding answer since I've had my plane in several months ago by the mechanic to take a look at the same issue that again was not able to be replicated and have flown probably 40 hours in that short time frame with no issue.
