Is the repair worthwhile?

The following points must be evaluated before considering a repair.

Blade wear

Blade thickness

Cracks in blades or blade roots

Missing diffuser ring

Propeller bush, look for evidence of slippage and propeller contact with gear-case

Propeller size and compatibility with boat setup.

Diameter

The Propeller Diameter should be measured to determine blade wear. See - Propeller Diameter

This measurement should be confirmed by proper identification of the propeller specifications.

See also - Identification

Pitch

Is the pitch correct for the boat/motor combination ? See also - Pitch

Boat performance and engine life is dependent on the correct propeller choice. To determine the correct propeller. A boat should be tested with a tachometer to find it's maximum achievable RPM, bearing in mind the following factors. Average conditions, load and trim angle. This information should then be compared against the motor manufacturer's recommendations. Although the manufacturers may quote a range from 5,000 to 5,500 rpm. I have found it preferable to be at the top of this Rpm range (5,500 Rpm) when choosing propellers.

Other points that should also be considered are the motors height and boat hull condition.

The wrong propeller choice can cause-

Engine overloading or excessive wear. Excessive fuel usage. Poor acceleration.

A smaller propeller is suggested to allow the motor to achieve it's correct rpm when considering skiing or carrying an excessive load.

The Propeller Bush

Inspect the propeller for the following - A Slippage marks. B Hub out of true. C Contact with gear-case.