Yanmar Marine Seawater Pump Flow Loss
The YANMAR-SALTWATER-PUMP (Yanmar) diesel fault code means: Yanmar Marine Seawater Pump Flow Loss. This is a critical severity code.
- Keep driving?
- No -- stop driving
- DIY difficulty
- intermediate
- Estimated cost
- $40-$600
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Common Symptoms
- No water from exhaust elbow
- Overheat alarm pending
Probable Causes (Ranked by Likelihood)
- Failed impeller (annual service item) Very Likely
- Worn pump cover plate Likely
- Seized pump shaft Possible
Step-by-Step Diagnostic Procedure
Close seacock.
Remove pump cover, inspect impeller and cover plate.
Replace impeller and gasket; lubricate with glycerin only (petroleum attacks rubber).
Frequently Asked Questions
What is Yanmar code MARINE-SW-PUMP?
Yanmar MARINE-SW-PUMP: Yanmar Marine Seawater Pump Flow Loss. This code is reported on Yanmar equipment running the described engine family.
Can I keep working with Yanmar code MARINE-SW-PUMP?
Do not continue operating. Risk of engine damage or unsafe shutdown.
How much does Yanmar MARINE-SW-PUMP cost to fix?
Typical repair cost: $40-$600. Off-road diesel shop labor runs $125-$175/hr in 2026. Dealer diagnostic software (Yanmar SmartAssist / YDT) is usually required.