Help for a boat rookie

Took my new (to me) boat out for third time today and it had no giddy up. I have been told that I need a new propeller because the inside has been worn out and it is no longer catching on the drive shaft. Seems like an easy job but I have no idea what propeller to buy. It is a 1982 Johnson 25 hp. I’m told that iboats is a good place to order the part but there are about 800 props to choose from. Any advice on size etc is appreciated

prop shop

Could be a spun hub. Is it surging? Like catching, then slipping? A prop shop can remove the old hub and press in a new one. You don’t necessarily need a new prop.

Does the prop appear to be in good condition otherwise? Not bent or dented?

Without more info, you may have other issues like dropping a cylinder. Those 2 strokes will appear to idle fine on one cylinder. When you put them under load they will bog down if one cylinder has no spark.

Does it rev way up under load? Feel free to PM me if you want to troubleshoot.

I should have been more clear. It is the spline that is blown on the prop, you can freely turn the prop with your hand around the drive shaft. My confusion is how to figure out what prop will work with the motor

Should be stamped on the prop housing.

Get a prop wrench, put the motor in gear or trim it down onto a block of wood so it doesn’t spin. Since you say it spins on the shaft, trimming it on the block of wood would probably be the best choice. When you remove the prop, stamped on either end will be the prop diameter and pitch.

Thanks super Dave!

Are the prop splines supposed to “shear” like that on Johnson motors if they hit something?

Anyway, should be the same as an Evinrude motor of the same era if that helps with finding a prop.

Likely a broken shear pin but could be a badly spun hub as well.Pull the prop off and there is a metal pin about an inch long,if that is broken in two replace and your back in business.If the pin is intact you will need a new or rebuilt prop.