did a forum search for humming this was a old post and there fix for it:
Originally Posted by allinon72
Well I found the problem. It was the foam on the intake shelf...it was completely deteriorated and allowing air to enter and make a whole lotta noise. Replaced the foam with high density foam from Lowes and it's completely gone and the engine is much quieter overall.
Last edited by hetman; 10-13-2012 at 11:47 PM.