MerCruiser Exhaust Riser to Dry Joint Manifold Gasket with Restricted Flow | Barr Marine MC47-27-864850 MerCruiser Exhaust Riser to Dry Joint Manifold Gasket with Restricted Flow For Mercruiser dry joint exhaust applications with one open and one restricted hole Restrictor gasket must be installed on all seawater cooled engines Installed between exhaust manifold and exhaust riser or elbow - see attachment Restricted end must be positioned to the seawater inlet side of the exaust elbow Replaces Mallory 9-61429, Sierra 18-0722 and Mercruiser Marine 27-864850A02