# 2005 15 HP Merc. Problem and Question



## cpauly33 (Dec 22, 2010)

I picked up a used Merc a couple months ago. It had sat and I had to do some work cleaning out all the ethanol gunk. Since then the motor runs great except one issue. At WOT there is a knocking, ping type noise. I don't know enough about motors to have any idea what going on. Its only at WOT and if I back the throttle down less than a 1/4 turn, still at full song, the sounds stops. I've changed the plugs and tried both Mid and High grade gas with no change.

I'd also like to know if it might be possible to upgrade my 2005 15hp to a 20hp? Maybe by changing out a couple parts. They seem to be pretty much the same motor.

Thank you


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## noeettica (Sep 23, 2007)

2 stroke or 4 stroke ?


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## cpauly33 (Dec 22, 2010)

4 Stroke


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