YANMAR-SALTWATER-PUMP critical Yanmar ›

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.

My Garage →
Keep driving?
No — stop driving
DIY difficulty
intermediate
Estimated cost
$40-$600

What Are the Symptoms of YANMAR-SALTWATER-PUMP?

  • No water from exhaust elbow
  • Overheat alarm pending

What Causes YANMAR-SALTWATER-PUMP? (Most Likely First)

  • Failed impeller (annual service item) Very Likely
  • Worn pump cover plate Likely
  • Seized pump shaft Possible

Can I Still Drive with YANMAR-SALTWATER-PUMP?

No — stop driving. YANMAR-SALTWATER-PUMP is rated critical severity. Continuing to drive in this state risks further damage — get it looked at before your next trip.

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?

Estimated repair cost: $40-$600. Off-road diesel shop labor runs $125-$175/hr in 2026. Dealer diagnostic software (Yanmar SmartAssist / YDT) is usually required.

Mechanics Guide Step-by-step diagnosis

How Do You Diagnose YANMAR-SALTWATER-PUMP?

  1. Close seacock.

  2. Remove pump cover, inspect impeller and cover plate.

  3. Replace impeller and gasket; lubricate with glycerin only (petroleum attacks rubber).

Which Vehicles Commonly Get YANMAR-SALTWATER-PUMP?

  • Hunter / Beneteau / Catalina sailboats with Yanmar 3JH / 4JH
  • Trawlers and sport fishing boats with Yanmar 6LY / 6LF series
  • Sailboat auxiliaries with Yanmar 2YM / 3YM / 3JH5 diesels
  • Commercial fishing vessels with Yanmar 6LY3-UTP
  • Yachts with Yanmar 6LY400 / 6LY440 / 8LV common-rail marine diesels
  • Workboats with Yanmar 4LV / 4JH series marine propulsion
  • Ski boats and express cruisers with Yanmar marine diesels
  • Tenders and RIBs with Yanmar 3YM20 / 3YM30 sailboat aux
  • Island-hopper ferries with Yanmar 6AYM / 6HYM commercial series
  • Tug boats and small workboats with Yanmar 6HAL-HTP / 6HYM

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