I have a mercruiser 165 with an alpha one(G1) out drive. I replaced a bad, very bad, impeller and I now have a leak out of the stern end of the heat exchange. Just a trickle at low RPM but when I increase RPM, trickle becomes a stream. When I have the muffs on, there is nothing coming out of the prop-exhaust. I am wondering if a piece of the old impeller is lodged somewhere. When I remove the hose that extends from the stern side of the heat exchange to the exhaust manifold, I do see water bubbling up. I removed the Oil cooler section of the section and it is clear and clean, so no obstruction from exhaust manifold to stern side of the heat exchange. Does anyone have a more detailed diagram of this? I see the diagram in the manual but it is not exactly as mine is. I do now know where to look for the jams but I am thinking that because this is a low pressure system, it would not take mush to jam it up.