OK, here it is.... some may disagree, but I have been flying for over 45 years, over 30,000 hours, ATP A&P IA CFI DAR. The skinny on engine management...
1. for certification, engines must meet the ability of running 50 hours at full rated power, maximum oil temperature, and maximum cylinder head temperature, and then be inspected, and no anomalies found!
2. I have torn down a lot of engines, many with coked up oil rings, coked up valves, excessive deposits on the piston, and excessive cylinder wear were from operators that thought they were "babying" their engines, running them rich. those that have been run at leak, show very little wear, low deposits, and most likely could keep running for a lot longer with reliability.
3. Most carbureted and fuel injected (non turbo) engines are set for an approximate 13/1 air to fuel ratio. The last bit of throttle enrichens the mixture even more for take off and climb. Throttling back in the climb where there is not as much air flow over the engine than in cruise will cause the EGT and CHT to climb (Bad!!). I leave the throttle full bore, after take off and cleaning up the aircraft, I leave the throttle parked full bore, but bring the prop back to 2500, if fixed prop, don't do a thing! Then, I take a peek at the EGT for any cylinder I like, and use that egt to lean to every 1000 feet or so. (That is the only time that the EGT value means anything to me). At level off, leave climb power in until cruise speed is reached, then reduce power to what you like for cruise, I use 21-22 inches and 2300 below 10K, and full throttle and 2400 above 10K. Then do the big "pull". I know my engines, and know what fuel flow I want to see that will represent "peak" at various power settings. I always lean to peak! Peak egt is a bit flat over the top, my engine runs about .3 gallons per hour from the first to last cylinder to peak. I split the difference. If you look carefully, you will notice that as you lean, the EGT and CHT both climb until about 100 degrees rich of peak, and leaning past that point, the egt continues to climb, but the CHT begins to drop. wonderful! Very efficient, low deposits in the engine, and she purrs like a kitten! So ask yourself, if you are burning less fuel, and the engine is running cooler, what is the problem again?
4. It's your engine, but from experience, there are a lot of old school guys still out there, think running very rich is treating the engine well, when just the opposite is true! (Remember when...probably don't... we sued to pull the prop through before every start to "limber the oil"? Total BS! It was a hangover from the radial engine days, preventing hydraulic lock starts.
5. If you get a chance, read all about running your engine from the articles written by John Deakin, mostly published in AvWeb. There is a lot of pure scientific data there, not old tales, but alas, still can't convince the poorly informed of their poor engine management!
fly Safe!
Regards,
DAR Gary