I just aquired a 1999 50hp Mercury bigfoot. It runs great once i get it in gear, but sometimes it seems to over rev itself. I was also idling and didn't touch the throttle control at all and it revved up a few hundred RPM. Could fouled plugs cause this? It will cycle up and down while in neutral if you just let it sit there for a minute or two. I have checked linkage and am 99% sure it is right as it closes the throttle all the way. Thanks in advance for the help.
