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Old 08-25-2007 | 10:49 PM
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RCKen
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From: Lawton, OK
Default RE: Nexstar "running in" engine


ORIGINAL: firestone1121

why does the manual say to not run the motor on full throttle for long periods until break in but the break in procedure says to run 2 tankfuls under full throttle conditions?? sounds like a chicken or the egg predicament.
While the throttle may be fully open, there are a few other things going on. Most notably is the needle valve setting. While breaking in you will lean out the mixture for a little bit, what they call "2-stroke". Then the engine is richened back up, called "4-stroke". When the engine is richened back up the excess fuel cools the engine off. By alternating back and forth the engine is gradually broken in. This is very much different that just setting the needle and opening the throttle up as you might see when flying the plane.

Ken