Custom Boat Manual

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When the temperature alarm sounds

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The first checks, in order: throttle back, exhaust water, seacock, strainer, impeller, belt, coolant — and when to call for a tow.

Sources (5)
  • On an overheat: ease back, neutral, shut down when safe; open the hatch; check raw-water intake and strainer; if the seacock is open but water will not draw, the impeller has likely failed; check belts and coolant tank; restart only after fixing the cause and shut down if temperature jumps in the first minute; steam at the exhaust means raw water is not reaching the riser; find a safe spot to drift or anchor; call for a tow if impeller vanes disappear into the cooling passages or it keeps overheating — seatow.com
  • Beware of hot engine coolant; the manifold has a pressure cap; strainer debris causes high temperature; check the exhaust elbow for carbon build-up; heat exchanger needs periodic cleaning (Westerbeke 55B/55C operators manual) — westerbeke.com
  • Check the coolant with the engine at room temperature and remove the expansion-tank cap slowly — boatus.com
  • A weak exhaust stream warns of impeller trouble; broken impeller pieces can go into the heat exchanger — impelpro.com
  • Overheating is often the first sign of restricted water flow in the exhaust elbow — 48north.com

General guidance for recreational boaters — your engine and equipment manuals and local regulations come first.