Signs Of Impeller Wear

Dec. 17, 2020

Signs Of Impeller Wear

The impellers pump cold water into the boat’s engine to cool it during use. If the quality of your impeller is not good, it may cause a big problem.

Common problems and treatment methods of the impeller

1)Casting defects

Failure performance: flow channel inclusions; fleshy; not smooth; trachoma; cracks; shrinkage, etc.

Treatment method: Grinding, repair welding, and other methods can be carried out according to the actual situation. If the problem is serious, it needs to be scrapped and recast.


Failure performance: The impeller of the process pump made of gray cast iron material is worn by water containing a small amount of cement foam within 5 years. The abrasion problem is more caused by the improper material selection of the design party or improper selection of pump type, or process The medium is contaminated.

Treatment method: change the impeller material; change the design scheme, change the pump type; check the process medium.


Failure performance: improper design scheme; high installation position; improper material selection, etc.

Treatment method: lower the installation position; change the material that is more resistant to cavitation; redesign the pump type.

4)Death surrounded by mouth

Failure performance: The design gap is too small; the hardness difference between the front and rear aperture rings is less than 50HBW; there are solid particles in the aperture ring gap; the aperture ring is deformed, etc.

Treatment method: increase the design gap; change the material of the mouth ring; check the process medium; replace the new mouth ring, etc.


Failure performance: caused by cavitation, corrosion, and abrasion; caused by poor casting quality; caused by water hammer.

Treatment method: replace with a new impeller.


Failure performance: the improper selection of materials.

Treatment method: replace the impeller with a new anti-corrosion material; coating the impeller anti-corrosion layer; spraying the impeller anti-corrosion layer.

How is the impeller damaged?

The boat's impellers are a series of rubber blades molded around the hub. The ends of these flexible blades can wear out for a variety of reasons due to the ease of use or the boat in sandy water. Abrasive sandlike material may wear down the impeller more quickly.

Impellers can also become rigid and brittle as the motor sits idle for several seasons or is exposed to high temperatures. Water - lubricated impeller, if the impeller dry, the impeller may be damaged in a few seconds.

What happens if the impeller fails?

If your impeller fails, the pump will not be able to pump the cold water into the engine, causing the engine to overheat. If you find that the impeller fails prematurely, you can avoid major problems. However, if you are not lucky enough to grab a bad impeller, the result can be disastrous for your engine.


What causes impellers to go bad?

Grinding sand can cause the impeller to wear out faster. Impellers can also become rigid and brittle as the motor sits idle for several seasons or is exposed to high temperatures. Water lubricates the impeller, and if it’s dry, the impeller may be damaged in a few seconds.

Impeller pump usually fails in one of two ways. First of all, the performance and flow of the pump gradually decreased. This is usually due to impeller or casing wear or impeller life. The second failure mode is a sudden catastrophic failure in which the impeller usually loses part or all of its blades.

In addition, how long can the impeller last? During spring commissioning and run every 200 hours, you should check the condition of the impeller. Properly installed impellers may last for several years, but you should stick to a schedule of preventive, instead of emergency maintenance.

Similarly, someone asked, how often should the impeller be changed?

Most mechanics and manufacturers recommend every 3 years because you don't want the bolts on the lower unit to stop beyond the actual wear of the customized impeller.

We are impeller suppliers. If you are interested in our products, please feel free to contact us.