Because the engine is often the single most expensive part of your boat, it makes sense to inspect or replace the risers and manifold periodically before an internal leak occurs, which is more a question of “when” than “if.” Once it happens, there is usually little or no warning before the engine is ruined.

When should risers and manifolds be replaced?

But they do need replacing every once in a while. Luckily, if you make sure they are properly maintained, you can increase the life span up to 10 - 20 years. On average, however, you'll have to replace them every 3 - 5 years.

When should I replace my manifold?

With raw-water-cooled engines used in salt water, you might expect their manifolds to have a three- to five-year life. Corrosion may warrant replacement in 10 years if an engine used in salt water has a closed cooling system.