If the timing is "fixed", why do you have to richen the fuel mixture when using a larger prop to eliminate preignition?

There is an interplay between all of the conditions in the engine. Just as the high speed needle affects the low speed setting and the low speed setting affects the high speed setting, on most glow engines, one can adjust when ignition occurs by varying the mixture, the load, the type of glow plug, the fuel mixture and even the amount of cooling air available to the engine. Not a terrific amount, but it does have an affect upon ignition timing.

I don't consider myself an expert, but I do consider myself to be experienced. Yes, I make mistakes sometimes. Usually I misspeak. Think one thing and type another. Other folks have been guilty of the same thing. Or perhaps they could have expressed themselves better. I know I always think of a better way of saying things once I have posted the article.

What disappoints me sometimes is that some folks are so concerned with what they perceive as their position on the social ladder, that they become terribly upset when someone disagrees with them. It reveals more about their personality than they could ever imagine.

I don't know about the rest of you, but I'm not perfect. Nor do I want to be. There was only one perfect man and look at what happened to him. <G>