1982 Johnson 50 HP water pump impeller key / pin?

[kayakndave]

Hello everyone. Just bought an 82' Johnson 50 Seahorse. Seems to run good, but guy said it wouldn't pump water. Dropped the lower and when I removed the impeller housing a pin fell out. This pin is about 3/4" long and pointed on both ends. Is this the impeller key? Never seen one like it. The impeller itself has the normal Square slot for a normal key, but the shaft on this motor doesn't have the corrosponding keyway groove, only a flat area on the shaft where the impeller mounts. Did he get the wrong impeller? Says he hasn't messed with it much and he bought a new impeller so he could run the motor for a perspective buyer. Any help would be greatly appreciated!

 

[Haffiman]

Re: 1982 Johnson 50 HP water pump impeller key / pin?

If a flat grinded surface on the shaft, they originally had a pin like you describe. Was later changed to a plastic wedge. The correct impeller should have room for the wedge and no key-way. Looks like a wrong impeller.

 

[kayakndave]

Re: 1982 Johnson 50 HP water pump impeller key / pin?

Thanks Haffiman. How does this pin hold the impeller in place? There isn't a hole in the shaft for the pin. Does anyone have pics of how this works? And I thought replacing the impeller would be a piece of cake....Silly Me.

 

[Haffiman]

Re: 1982 Johnson 50 HP water pump impeller key / pin?

Put the pin, use some grease, on the flat surface, parallel to the shaft. Slide the impeller on top. It will lock the impeller when shaft turns and impeller gets resistance. However most impeller comes with the new wedge in the package. To get impeller off, hold it, turn shaft counter and it gets released.