I have a 96 Merc 454 with 80 hours in a 75 Carver (new boat to me) in fresh water with fresh water cooling. The engine runs good and after our first overnighter we returned and I smelled something that made me nervous.
I opened the hatch to smell what I thought was old burned rubber, not bad but enough to make me look around! I returned the next week to inspect and ran the engine at about 2000 for about 15 minutes and saw wisps of smoke coming off the starboard riser hose (bellows) the one that connects the riser to the elbow. The riser was hotter than the port side and the engine temp was about 160.
I drained the manifold and lifted the riser off the manifold to inspect and it looked clear, I could not get the hose off to look in the other end at the exhaust exit. I then removed the intake pump and removed the impeller to see it wasn't in great shape! I installed the updated Mercury kit and refired the engine, checked for leaks and then let it run for about 15 minutes again. This time both manifolds were cool, however at the top rear of the hose coupling the riser to the elbow wisps of smoke still were present and it is hot! The front of the hose at the riser is cool and the other side is fine.
What should I be looking for or what should I do?
Thanks
I opened the hatch to smell what I thought was old burned rubber, not bad but enough to make me look around! I returned the next week to inspect and ran the engine at about 2000 for about 15 minutes and saw wisps of smoke coming off the starboard riser hose (bellows) the one that connects the riser to the elbow. The riser was hotter than the port side and the engine temp was about 160.
I drained the manifold and lifted the riser off the manifold to inspect and it looked clear, I could not get the hose off to look in the other end at the exhaust exit. I then removed the intake pump and removed the impeller to see it wasn't in great shape! I installed the updated Mercury kit and refired the engine, checked for leaks and then let it run for about 15 minutes again. This time both manifolds were cool, however at the top rear of the hose coupling the riser to the elbow wisps of smoke still were present and it is hot! The front of the hose at the riser is cool and the other side is fine.
What should I be looking for or what should I do?
Thanks