On my 1979 Mercruiser 260hp 5.7L 350 serial number 5432443 with end risers manifolds when I took the elbow off the manifold it had a metal plate in between the two with a gasket on each side...I only expected to see a gasket. Can someone tell me why it blocks off the one water jacket and if I need to replace it or disgard it? It's just a standard i/o drive with power steering, it's not a direct drive or closed cooling..nothing like that.
Whats throwing me is I bought another set of risers for the same motor same year and they definitely did not have this same plate in between the manifold and the elbow. What else is odd is with the previous manifolds, the ones with the plate, I was getting water in the oil, but with the replacement ones without the plate I haven't had a drop in there. I tried doing the recommended acetone test on the older manifolds to see if I could find a crack but either there isn't a crack or I was performing the test wrong.
Whats throwing me is I bought another set of risers for the same motor same year and they definitely did not have this same plate in between the manifold and the elbow. What else is odd is with the previous manifolds, the ones with the plate, I was getting water in the oil, but with the replacement ones without the plate I haven't had a drop in there. I tried doing the recommended acetone test on the older manifolds to see if I could find a crack but either there isn't a crack or I was performing the test wrong.
