how to read a prop

[locked and loaded]

can some one help me here?I want to know about my props.The motor is a 75 johnson 25hp electric start i have 2 props and wondering if either are ok for this application props are as follow prop #1 reads D1 322011 9 1/4 x 11
prop #2 reads Michigan Q12010

can some one tell me what all this means and which one to put on or get a new one

 

[5150abf]

Re: how to read a prop

The first number is the diameter, the second the pitch.

Pitch has more effect than diameter on performance, it is the angle the blade hits the water, in effect higher pitch is like shifting to a higher gear in your car.

You should choose a prop to obtain an optimum RPM, usually between 4500 and 5500, but this varies, so to see which prop you should use you need to know what RPM is recommended for your motor and then a tach to see if you are getting it then you can adjust from there.