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Old 09-11-2017, 06:15 PM   #4
40 Deluxe
Senior Member
 
Join Date: May 2010
Location: now Kuna, Idaho
Posts: 3,774
Default Re: Newbie knocking paranoia/ignorance

Possibly an exhaust leak at one of the ports. A leak at one port can sound like a knock, plus exhaust pressure is higher when the engine is pulling or when the spark is retarded, so will sound louder. Open the hood and snap the throttle open while listening. An exhaust leak sounds more like a 'spit' than a 'knock' but some experience is needed to identify. If you suspect an exhaust leak, pull the manifold and look for a burned gasket or trace of black soot. If it is a leak, remember that sound!
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