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<DIV><FONT face="Comic Sans MS" size=2><STRONG> You know, I don't usually say to much and keep my mouth shut most of the time on this list, but it's time someone spoke up on this issue. In the last several months there has been several thousand posts on this discussion group about 2 strokes, adjusting pipe length and tuning 2 strokes, bearing issues, sealed vs not, stainless vs not, after market vs standard factory bearings, gee, I got 200 flights on my stainless bearings vs 30 flights on the factory bearings, after run oil for 2 strokes, whether to use it or not, whether to run them dry after flying or not, dual plug heads vs single plug heads, and so on....</STRONG></FONT></DIV>
<DIV><STRONG><FONT face="Comic Sans MS"> In the last several months I have only seen less that a dozen posts about a YS engine, and most of those were how to type questions, not problem issues. Last week there was one post about which port to hook up the return fuel line to, and Don Ramsey's problem with his YS. How do you figure that you could not get a word in edgewise????? I guess that when some folks start flying 2 strokes, they forget how to count........As some would say....flame suit on.......Larry.....</FONT></STRONG></DIV>
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<DIV><FONT face=Arial size=2>Brian,</FONT></DIV>
<DIV><FONT face=Arial size=2>Interesting ying and yang here on engines. 2 stroke tuning problems don't arise that often, and<FONT color=#ff0000> last week you couldn't get a word in edgewise for all the YS blues!!</FONT></FONT></DIV>
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<DIV><FONT face=Arial size=2>it's not common that the midrange would be lean, especially on the full Mintor setup. I haven't seen that. The pipe is an essential part of balancing the mixture in a 2 stroke and I know the Mintor pipe produces an even mixture, even if not top power. Please check the engine cooling. This can significantly affect performance. Fly with the cowl off for comparison. If there's a difference, then maybe you need more exit area, or another hole in the bottom of the chin cowl behind the engine. </FONT></DIV>
<DIV><FONT face=Arial size=2> If the engine is lean in midrange it will get very hot in the air and this is not good. I've seen one engine where the owner decreased teh pump pressure so much that it went lean in midrange and he nearly burned it up. Are you still at the factory pump setting? If you've decreased the pump pressure, then increase it again. If you are flying 10%, then increase to 15%. Some engines of early vintage prefer a bit more nitro. Another way to richen the midrange is to shorten the header. This is not my first suggestion though, because the factory setup works fine, however I've experimented with doing this and found that the 170 will gain a lot more power on a slightly shorter pipe at the expense of a richer midrange. Normally, this is a bad thing.</FONT></DIV>
<DIV><FONT face=Arial size=2> I have had good luck with setting everything a slight bit rich on the ground. This is not because I'm expecting it to lean out in the air, but because I think it helps the engine slow down faster and it doesnt' spool up on downlines. </FONT></DIV>
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<DIV><FONT face=Arial size=2>--Lance</FONT></DIV></BODY></HTML>