Under high RPMs (>2700), my 1969 Mercruiser 120hp 2.5L makes one relatively loud click followed by a very short drop in power then resumes normal operations. This happens within 1 second. I just installed a new head block, so thought that may have something to do with it. It almost sounds like a...
I have a 1969 Mercruiser 120hp 2.5L i4. Thought I blew the head gasket due to milky oil and water shooting out of spark plug holes. She'd turn over but wouldn't fire. When I took off the head, I found a puncture in the head next to the valves (see photo). Cylinder 1 is rusty but no visible...
