by Tom
(Moon, VA)
My 1990 Mercury, 90hp has been purring like a kitten....until yesterday. While out fishing the motor started knocking, or more like "clacking". Runs fine, no smoke, good water output, just a constant clacking in the head area. It doesn't sound deeply internal, like a rod or piston, more like a playing card in the spokes of a bicycle. We idled back home, about two miles, without a problem, just the loud clacking. Any help will be appreciated. One old Mercury fan suggested that it sounds like a magnet came loose on the flywheel...possibility?