Craftsman 900.370510 emits rhythmic noise

[the.doc]

This is an electric mower. It runs but emits a rhythmic noise. There's a link at the bottom to an imgur file with a .MOV video.

It was given to me recently; I just tried it yesterday and got this noise. I bought an electric back in the 1970s and used it for 40some years. Trashed it when I ran it into a tree root and (I think) bent the motor shaft.

Any help with this much appreciated.

https://imgur.com/a/R97rjJO

 

[Rivets]

Harmonic ringing on an electric mower is normally caused by either a blade which is unbalanced or a motor going bad. I would remove the blade and run the mower. Noise gone blade bent or unbalanced. Noise still there, motor going bad.

 

[the.doc]

Sounds worse with the blade off. Not good news.

Got to be the bearings I reckon; I'm tempted to tear it down far enough to look.

https://imgur.com/a/92wkM7k

thanks for the help

 

[Tiger Small Engine]

Harmonic ringing on an electric mower is normally caused by either a blade which is unbalanced or a motor going bad. I would remove the blade and run the mower. Noise gone blade bent or unbalanced. Noise still there, motor going bad.

I bet you won’t get 40 years out of this new electric mower like the one from the 70’s. I assume by electric you mean battery now. You will be lucky to get 4 years before you have to replace the battery.