Systems
Marine exhaust manifold, riser and elbow service
Wet exhaust systems mix hot exhaust gas with raw sea water, which corrodes manifolds, risers and elbows from the inside out. When one perforates, sea water goes into the cylinders. This is one of the most common ways a healthy marine diesel is destroyed, and it is entirely preventable with inspection.
An exhaust elbow fails from the inside
The outside of a riser can look serviceable while the inside has rusted to a shell. That is why exhaust components are inspected internally on a schedule and replaced on age rather than appearance. Water entering a cylinder through a failed elbow can hydrolock and bend a rod in a single start.
What is included
- Manifold, riser and elbow internal inspection
- Flushing of exhaust and cooling passages
- Corrosion assessment and remaining life estimate
- Component replacement
- Hose, clamp and muffler condition inspection
- Water intrusion diagnosis
How it works
Inspect internally
Components come apart or get scoped. External appearance is not evidence of internal condition.
Flush or replace
Passages get flushed where the component has life left, and replaced where it does not.
Check the whole path
Hoses, clamps, muffler and lift height all get looked at, because the failure often sits downstream of the part that got blamed.
In a marine wet exhaust system, exhaust risers and elbows corrode internally while appearing serviceable externally, and a perforated elbow can admit sea water into the cylinders and hydrolock the engine on the next start.
Related systems work
Marine Generator Service
Service, repair and load testing for marine generators, the system that keeps air conditioning and power alive at anchor.
Marine Transmission Service
Gearbox service, fluid analysis, coupling and alignment work on marine transmissions and drive systems.
Cooling System Service
Raw water and closed loop cooling service, flushing and repair, the system that causes most marine diesel overheats.
Exhaust System Service: common questions
How often should exhaust risers be replaced?
They are typically replaced on age and inspection rather than on failure, because failure means water in the engine. Inspect internally on a schedule and plan replacement before the component reaches the end of its life.
What is hydrolock?
Water entering a cylinder where it cannot be compressed. When the engine turns over, something has to give, which is usually a connecting rod. It is a catastrophic and completely avoidable failure.
Can you tell if water has already entered the engine?
Yes. Borescope inspection shows water staining and rust on the cylinder walls and piston crowns, and compression testing shows the consequences. Both are part of a mechanical survey.
Tell me what the engine is doing
Describe the symptom on the phone and most of the time the problem is narrowed before I arrive. Surveys are booked around your sea trial date.