Originally Posted by
exocet-RCU
So gentlemen, remind me of the break in process. If I remember correctly, I run the first tank in '4 cycle' extra rich mode. Let it cool down. Then run again, leaning it out so it alternates between 2-cycle and 4-cycle. Let it cool down. Then run again, leaning out a little more so it is now fully in 2-cycle but NOT fully peaked out. Let it cool down again and then run it again leaner but not quite at full. Does this sound correct?
That pretty much covers it. The first "extra rich" run is to get any manufacturing junk, polish, etc. out of the engine. After that, it pretty much depends on how tight your engine is. If at any time the engine starts to "sag" or slow down, shut it down immediately. That means it is over-heating and needs to cool. After it cools, richen the needle a few clicks and run it again.
Some engines you can run right up to peak for a couple of minutes, then pull or pinch the fuel line to shut it down. Let it cool to ambient temperature. That completes one heat cycle. Other engines need to be run very rich for two minutes then pull the fuel line and let it cool. These engines are leaned a couple of clicks every other heat cycle. When it runs well at peak it is ready for a plane.
Oh, another point, break-in is best accomplished on a bench where you have full control at all times. At no time should you run the engine over lean.
Of course there are other ways to accomplish break-in but I like and use this method.
George