ORIGINAL: Not24
Does anybody think the 10% fuel could be causing detonation with the lighter loaded prop? It is my first guess, but I have no 5% fuel to test my theory. I have read that people are happy with 0% all the way up to 20%, depending on who you talk to. This has got to be the most controversial engine ever built!
As I re read some of these posts, it seems as if it is assumed that the engine is running rich in the midrange. I'm not so sure that has ever been established. Again, on a new engine, I should be able to run it good and rich in flight till I'm sure it's good and broken in without it quitting. I'm more inclined to believe that I have my exhaust a little too restricted for proper breathing. Perhaps I will play with the muffler(s) a little before tapping the backplate for the pump.
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I do believe in serendipity. However, most of the time when serendipity enters my life, it is of a negative nature. Kind of like when an engine quits for no apparent reason.
I have had this happen to me several times over the years. The engine quit once, causing a deadstick, then, just for kicks, after remembering the sound of the engine when it quit and ascertaining that it was not lean prior to quitting, I would fire it back up again, with needles untouched and continue to fly the rest of the day without incidence. It happens. It has happened to me several times over the decades. Why? Hellifino...
This is not to say that there wasn't a real reason for the engine to quit. I'm not much into magic, so I don't think that was it. Whatever the problem is, I hope you get back to us with the solution. I'm still leaning toward fuel foaming with the suspect prop.