<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META content="text/html; charset=utf-8" http-equiv=Content-Type>
<META name=GENERATOR content="MSHTML 8.00.6001.23588">
<STYLE></STYLE>
</HEAD>
<BODY style="MARGIN-BOTTOM: 45px" bgColor=#ffffff>
<DIV><FONT size=2>The factory anti-runon system is passing air all the time
the engine is running, to purge the charcoal canister and crankcase using
the suction from the carb(s). </FONT><FONT size=2>When you turn off the
ignition the valve closes, which allows a higher level of vacuum to develop in
the plumbing, and that sucks the fuel out of the carb jet(s) to prevent
running-on.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>So if any of the many components, hoses or joints in
the system are leaking it could create the noise you are hearing. You can
pinch off various hoses and if the noise stops you know the source is beyond
that point, and can move on to the next.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>It could, of course be a number of other things like fanbelt,
fan, water pump, alternator etc.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>PaulH.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<BLOCKQUOTE
style="BORDER-LEFT: #000000 2px solid; PADDING-LEFT: 5px; PADDING-RIGHT: 0px; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV>But I've noticed when I rev the engine to 3500rpm between shifts, there
is an odd whistling noise that comes from under the hood. Sounds like it's
coming from the anti run on valve area, but I can't confirm that. </DIV>
<DIV style="FONT-SIZE: 10pt"> </DIV></BLOCKQUOTE></BODY></HTML>