Flexible impeller pumps

Usually inboard and stern-drive engines  include a raw water pump of the flexible impeller type. Flexible impeller pumps are common in shower drain sump pumps, some bilge pumps, wakeboard ballast pump systems, oil changing systems and lots of other applications.

When they fail

Flexible impeller pumps work best when run regularly. If your pump sits for months with the impeller in one position with the blades on one side bent, it may “take a set” and may blow a circuit breaker on startup (if it’s electrically driven). The impeller may also stick to the housing and come apart when the pump starts. Impellers are damaged by debris that get sucked in, by chemicals, and especially by running dry. All it takes is a plastic bag blocking the raw water inlet, or a seacock left closed when you start your engine, and your impeller will soon be a shredded mess.

Of course, you should check the wet exhaust on your transom for the proper flow of cooling water each time you start the engine. You should check the impeller’s condition during Spring Commissioning and every 200 hours of operation. Correctly installed impellers may last for several years, but you should stick to a schedule of preventative instead of emergency maintenance. Just the same, an impeller will eventually fail while in operation, and usually at an inconvenient time. You should carry a spare onboard, since the impeller is one of the vital components of your engine’s cooling system.

Choose the right impeller

AMIC had produced  impellers for several years , OEM for many famous company , the flexible impeller quality feedback is good .

  • You can find the part number form AMICproducts list and chose the right impeller .
  • You can also remove the impeller from the pump
  • The correct AMICnumber for a replacement impeller can also be determined according to the number of blades, diameter (Dimension A), impeller depth (Dimension B) and shaft diameter (Dimension C).

Material :Neoprene, Nitrile or Polyurethane

Use neoprene impellers for engine cooling, and for fresh and salt water transfer duties. Neoprene is suitable only for pumps where small amounts of oil or diesel fuel are present.

Use nitrile impellers for bilge pumping and for transfer duties where water is heavily contaminated, for example by oil or diesel. For transferring diesel fuel, use a sliding vane pump like the Jabsco Vane Puppy or Groco Flo-Master. Ballast pumps, used on boats that tow wakeboarders, have unique requirements, needing to reverse direction and withstand systematic abuse. Polyurethane impellers are used in that application.