It was a gorgeous VFR day, and we were flying in an Aerostar 601. The destination was an airport in Alabama and I was really looking forward to this trip. But soon after we leveled off at ten thousand feet and got the engines set and properly leaned, a strange but definite engine roughness occurred. After some troubleshooting (as much as you can do in flight) we decided to turn back and fly home (not good to be a few states away from home with a maintenance problem if you can help it. Here’s a photo of the instrument panel after we had reduced power on the right engine: Listen to the audio for today’s podcast episode to hear the details. Note the high fuel flow indication on the right engine, even though the power has been reduced. Also, the EGT and CHT are indicating low for the right engine as well. After returning safely to SHD, I uncowled the right engine and ended up meticulously cleaning out the fuel injectors on the right engine, as well as the air lines and hose connectors that provide turbo air pressure to the fuel injector nozzles. In that process, I discovered some small black particles that may have been a contributor to one or more clogged / partially clogged. fuel injectors. Take a look: Also notice in the following photo the “GAUGE” fitting that is in the side of the engine fuel flow divider or “manifold valve.” This line goes to the fuel flow gauge in the instrument panel, and would explain why the fuel flow showed higher than normal on the right engine. If a fuel injector is partially or fully clogged, it raises the pressure at this fitting on the flow divider, thereby causing an erroneously high fuel flow indication on the gauge in the instrument panel. Here’s another photo for more context of where the flow divider is located on top of the engine: Unfortunately, this airplane does not have a graphic engine monitor. It would have been very helpful to see all 6 EGT’s and all 6 CHT’s on that flight. Instead, there is only one EGT probe and one CHT probe, and they are both located near cylinder #5 on the right aft side of the engine. (This is likely one of the cylinders that had a clogged / partially clogged fuel injector, since the EGT and CHT gauges were indicating significantly lower than normal. Let me know if you have any additional thoughts about this situation, and I’ll see you in the next episode! The post “257 – Rough Engine: Go Back Home!” appeared first at AirplaneOwner Maintenance.com