water pump impeller question

[gullake]

I have replaced the water pump housing and impeller on my '61 Johnson 40. Twice since then I have had the lower unit removed for repairs and decided to inspect the pump. Both times when I removed the pump I found two of the impeller vanes turned the wrong way. (Impeller is otherwise in good shape with no visible damage). I am certain I had all the vanes positioned correctly when I installed it. It's hard to believe it has been running that way without damaging the impeller. This motor ran fine all last season with a constant stream from my retrofitted tell tale nozzle. My only logical conclusion is that I must have inadvertently turned the motor backwards slightly while working on it and if it had been rotated in the proper direction the vaned would have straightened back out. I also wonder if this could happen on shut down if a motor kicks back slightly. Has anybody had this happen or have any thoughts on this.

thanks, gullake

 

[Mas]

Re: water pump impeller question

The vanes are flexible and should realign when the motor is turned in the proper direction...clockwise. If the vanes are not flexible, it should be replaced. The impeller should last several years before replacing. If it is only a year or two old and is no longer flexible, you may have an overheating condition.

Mas

 

[1946Zephyr]

Re: water pump impeller question

Chances are, the vanes sat in the reverse state for several months, therefore, they stayed that way.

 

[F_R]

Re: water pump impeller question

It is common for a motor to bounce back off the last compression stroke when it stops. That can kick a vane backwards. They normally will straightenout when you run it. Some motors (not yours) deliberately have a lot of slop in the impeller keyway to let it kick back without bending the blades backwards.