johnson impeller question

Replaced my impeller this morning on my 1975 50 hp johnson and when I turned the impeller it spun on the shaft and when I pulled it off there was no woodruff key. (motor is new to me) when I got everything clean and went to replace the impeller with a new one the woodruff key did not fit. I tapped on the new impeller and made a mark on each side and ground it down ( more like a shear pin) and was able to install the impeller and when I turned the shaft I could tell the impeller was turning but this does not seem right to me and it was obvious that the last guy could not get the key in either so he did not bother. No wear at all on the replaced impeller, no water when running prompted all this. ( I'll save for next time around) Bought the kit from Iboats. Anybody ever seen this? Thanks

Re: johnson impeller question

better check compression and look for signs of overheating. At minimum, you'll likely need a head gasket if this thing ever ran after the poor install.....


Cheers....

Re: johnson impeller question

I did earlier the compression is fine and it did run just no water...looks like the last guy just gave up

Re: johnson impeller question

If it is the model that you stated then there is a key to drive the impeller.
Sometimes the key slot in the shaft becomes damaged and the key will not press in. You could have the wrong impeller.
When you fit the impeller after it is located on the key, press down on the housing whilst rotating the shaft clockwise. This will ensure that the blades are correctly orientated. Be sure that the base plate and the housing have no grooving as this will prevent the impeller from sealing and pumping.

Re: johnson impeller question

My last water pump job, I used the sierra kit from iboats. The impeller I got was the right part number, but wouldn't fit over the drive shaft -- just a hair too much copper material left on the inner hub. I called, they sent a new one out right away, no problem. So, if you got a sierra kit, maybe yours was made the same day mine was?

If you're getting a good strong pee stream, I'd call it good.

Re: johnson impeller question

Thanks for the input guy's, It's raining here and I took the opportunity to rebuild the carbs and they are not on yet so I don't know if is working properly. But... the shaft for the impeller did not have a slot for the key it had a flat spot and I could see the imprint of a key in the past but it could not have been a woodruff key it would have to be a flat key ??? the impeller was the same size as the one I took out and I replaced the base plate while I was in there. Hard to say what someone did in the past... different lower unit?