Yes – 311484 is the number on your prop, not 111484.
Props for your motor will interchange with Johnson/Evinrude 15, 18, and 25 HP models from the 1950s.
The 277212 is a 9 x 10 prop, so it has one more extra inch of pitch than the one you have. It will go faster, but have more trouble planeing off heavier boats. The correct prop for your motor depends on the load your boat puts on it.
Here’s a link that ID’s the size and the Michigan prop replacement:
http://www.propmd.com/propeller-list/oe … 77212.html
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Propco has several sizes available that will fit – click on the link below and scroll down to 15, 18, 20, 25 HP pin drive props and you will find options from 9 to 11 inch pitch and there is an application code in one column that is explained at the top of the page to help select. The best way is to put your prop on, hook up a tachometer and see if wide open throttle has it in the max RPM range for your motor.
http://propcopropellers.com/evinrude_Outboard_Prop.htm
Dave
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