BoatHowTo · video

What this video covers

Nigel Calder explains why the 500-hour exhaust mixing elbow replacement interval on Yanmar engines is a manufacturer worst-case figure, not a universal rule.0:35 The mixing elbow is where raw seawater injects into the exhaust stream; the combination of saltwater and exhaust heat drives galvanic corrosion that is invisible from the outside until the elbow has already failed.0:43 At 50 engine hours per year, 500 hours equals 10 years, and actual lifespan varies widely depending on whether the boat is winterised with antifreeze to flush salt out or left with saltwater sitting in the elbow all season.0:59 Calder recommends pulling the hoses annually and inspecting the elbow interior visually — external appearance alone is not a reliable indicator.1:20 Some elbows last well beyond 10 years; others fail in two.1:53 A failed elbow risks exhaust gases entering the boat, making it a safety-critical component.1:57 Carbon buildup inside the elbow is a secondary warning sign, indicating the engine is being underloaded — a common sailboat problem that requires changing the duty cycle to add more load.2:22

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