Riser and Mainfolds in Freshwater

cuppa · Post by **cuppa** » Mon Jul 21, 2008 3:22 pm

How often do Risers and manifold have to be changed on a freshwater boat?

Danny Bailey · Post by **Danny Bailey** » Mon Jul 21, 2008 8:22 pm

It depends on how fresh the water is. When I was a teenager, I crabbed a boat during the summer that had a two cylinder marine engine that was almost 30 years old and the whole engine was raw water cooled. The more salt content in the water passing through the parts, the quicker the iron leaches out of them. If the water is truly fresh, the parts could last indefinately. If in doubt, pull a riser off, see what it looks like inside the water jacket, and then let it dry out for a couple of weeks. If it doesn't split, it's good to go back in service.