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<DIV><FONT face=Arial size=2>Colin,</FONT></DIV>
<DIV><FONT face=Arial size=2>Well we're making progress, but your data does not
match most OS140RXs. A duel plug head will help a bit, but that's a step
to refine a good setup, not make a good one from a touchy setup. The
touchiness you describe and the rich midrange on such a long pipe gives this
problem away.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>What elevation do you fly at? You may be at a
veyr high altitude, which is influencing the tuning and will require less pump
pressure. The other scenario is that your engine just came from the
factory with a bit too much pump pressure. Either case, the solution is
the same. You have too much pump pressure.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Depending on how meticulous you want to be there's
the 80/20 rule or the 99% rule. for 80/20, unscrew the pump screw 3/4 turn
and richen the idle a little bit. This will be close and you should find
the pipe setting much less touchy. use the techniques earlier to find the right
length. Since length is directly related to port timing, the ideal length
should not change theoretically, but I think you are longer than ideal because
your bigger problem is too much pump and you are way off the ideal pipe length
just to lean the midrange. If you want to confirm that the baffles were
put in correctly, insert a small dowel down the neck past the first angle to the
main baffle. Let me know the distance. Also, the distance the front
of the angle baffle. The other setup option is to set it to 31" and reduce
the pump pressure until you get a good midrange, then test fly and listen to see
if it sags on uplines. If so, increase pump until it runs
consistent. thi smight require a small access hole in your firewall to
simplify adjustments.</FONT></DIV>
<DIV><FONT face=Arial size=2>--Lance</FONT></DIV>
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