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<P><FONT SIZE=2 FACE="Arial">Greetings,</FONT>
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<P><FONT SIZE=2 FACE="Arial">I have a question about the YS 160 in my Abbra. I've got about two dozen flights on the plane/engine, since I bought it (used). It's run great up until yesterday, when I barely got one flight on it. I got as far as the square loop in the intermediate sequence (yeah, first maneuver), and it sputtered and choked at the top of the vertical line and across the inverted horizontal top line. I rolled it over, and it seemed okay, so I tried again. Same result. I got it back down without incident and ran the engine on the bench, and it was lean in the mid-range and top end. It got very hot during the short time I ran it on the bench, and it seemed to get leaner the longer it ran. I tried the high-end needle and small rich adjustment on the pump, but neither helped. It ran great last weekend, so I don't think it was a mixture setting. I then started checking the fuel lines and vent lines, but they seemed okay. Then I noticed the check valve on the head would rotate. The one on my other 160 doesn't rotate, and since I thought those were a press-fit, it doesn't seem like it ought to rotate. I gave it a gentle tug, and it didn't come out of the head, but it rotates pretty freely.</FONT></P>
<P><FONT SIZE=2 FACE="Arial">Is that a bad thing? Or should I continue looking for an air leak in other places? Any other suggestions?</FONT>
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<P><FONT SIZE=2 FACE="Arial">Does that check valve just pull off, and I can I replace it by just pushing another one on? Can it be that easy? :)<BR>
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Thanks!<BR>
Bob</FONT>
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