Is anybody familiar with the inner exhaust mainifold on a 3cy yammy? Im having some overheat problems at high rpms. Have changed out impeller and housings upper and lower. New thermostat,new pop off valve and cleaned the head and replaced the inner exhaust manifold baffle. My question is inside the exhaust manifold there are 5 small ports going from top to bottom( basicly on top and bottom of the cylinders) these little ports seem to be clogged with deposit. Do they feed threw the block into the head? Thats really the only blockage Ive been able to find. Engine runs beautiful, pumps water like it should be but at WOT after bout 30 secs she shuts down and alarms. Thanks in advance for any help!
