Re: Help with part numbers, problem solved, my error
ok... One of the weakest points on Mercruiser engines was the manifold to elbow joint. When the corrosion started attacking, it took out the metal around that joint pretty quickly (as you have no doubt found out), and a lot of wet stuff got to go where is shouldn't; straight into the engine cylinders, passed the piston rings and into the sump; where it has a great time with the local resident, oil, and basically screws up an otherwise perfectly good engine. The older system is now known as 'wet joint', because the joint itself carries the water. Around 2003 Mercruiser updated this area (not before time too!) and did away with the water flowing all the way through the manifold across the gasket surface and into the elbow. They got smart and closed off the top of the water ports in the manifold and elbow, made a couple of new passages (effectively on the 'outside' of the manifold and elbow) and routed the water through those, creating a dry joint at the manifold/elbow interface. They also shaped the gasket in such a way that if any water were to flow back towards the exhaust ports a 'drip tray' would catch it. This 'drip tray' is also in the path of the exhaust gas that has recently departed the cylinders, hence it's a tad warm. The 'drip tray' glows a lovely shade of deep red and the water disappears in a puff of steam, literally!!!
Hope I've helped.
Chris...........
I've added a couple of drawings if that helps (one of each system)....
