Reply To: Random questions about my 1958 Johnson RDS 20

[David Stanton]

At the link below, scroll down until you find your motor in the left column – be sure it says “pin Drive”.  You will find props up to 14 inch pitch.  Higher pitch = more speed as long as the load isn’t heavy enough to make the motor lug down.  Note the “Application” column with abbreviations defined at the top of the chart.  For your light boat, you probably want the 13-1/4 or 14 inch pitch.  I’d start with the 13-1/4 because the 14s are often used for dual motor setups.   Like Crosbyman said, using a tachometer to see where you are at is best way, but not everyone has several props laying around to try out.

https://propcomarinepropellers.com/pages/evinrude-johnson-propeller-specifications

Here is a link to cheap, easy to hook up and use tachs Crosbyman mentioned:

https://www.amazon.com/s?k=tiny+tach+tachometer&crid=XND0N3R82I3V&sprefix=tiny+tach%2Caps%2C175&ref=nb_sb_ss_ts-doa-p_2_9