In light of the engine problems involving Robin Leach’s trip down under and Kevin’s comments posted below, I think it is important to pass on some thing regarding my engine and the automatic altitude compensating mixture control that might be of interest to those you out flying.
In late June I took my plane to DLH for it annual check up, admittedly a little early, but I figured better then than just before OSH. I voiced some concern over a number of things many of which were minor, such as the pilot’s door did not open or close as easy as the passenger door, and virtually all were resolved. While most everything seemed to be in order, we talked about how hot my engine would get in an extended climb. I indicated that my fuel flow never has shown 18 GPH at takeoff even at Sea Level as Bill Marvel and Robin Leach experienced on their trip back to the West Coast at even higher altitudes.
As a result Cirrus spent considerable time investigating and adjusting the fuel system. First, my injectors were filthy (likely the result of dirty fuel that fuel filters do not stop) and were cleaned. Second, the altitude mixture control was replaced and/or calibrated. In addition, Cirrus adjusted the throttle/prop control interface. In total, Cirrus ran my engine for over three hours, which gives me the impression that the adjustments and sensitivity take some expertise to make right. It also worries me that if it takes Cirrus that long to make adjustments, how long will it take “mere mortals” at other shops to make the adjustments.
After the adjustments, I now note the engine “sucks” up much more fuel than it did before AND, more importantly, the engine and oil temps are cooler. I am delighted that both of those are cooler and the fuel burn overall isn’t appreciably more than before, but the plane does not fly as fast Â… getting about 155 TAS. The other factor that has me concerned is the engine does not run smoothly at low idle. It, in my view, seems to be running too rich, but the mixture control is “automatic”!? Cirrus and our folks at Del Monte are going to do some more testing and tweaking, but Â…. We’ll see.
As a result of my concerns, I am having a Graphic Engine Monitor installed that includes 6 probes for each of CHT and EGT. I am losing faith in the “automatic system.” I want to know exactly how the engine is performing. The GEM gives you graphic feedback on all six cylinders at the same time. Differences will become apparent right away and you are then better informed about whether or not you engine is being properly “fed” or not. I would suggest to those of you that have any concern that a GEM ought to be considered. Cost - about $2,000. It could be cheap insurance and reduce future engine maintenance bills.