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.

 

[ILENGINE]

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.

Or the mower because the battery was obsolete before the mower was even purchased.

 

[StarTech]

this mower runs household AC so no battery.

 

[the.doc]

this mower runs household AC so no battery.

Correct.

A friend bought a new mower and gave this one to me when the noise started. I never got around to asking how old it is. I took it because electric mowers have very few moving parts, and sometimes I can fix things. The old one had the motor sitting right there on top of the deck and very easy to get to. This one is completely enclosed in a plastic housing, so I have some work to do just to get a look at it. The plan is to take the motor out and look at the bearings. If they're bad and I can get replacements, I'll continue; otherwise it's for the dump.

I'm doing this because some of you guys told me that my riding mower is about to blow a head gasket. I don't see myself fixing that.

Thanks, guys; this is the most helpful forum that I know about.

 

[the.doc]

I took the cover off, which wasn't easy, and found an unbelievable amount of dirt that had collected inside. About a half hour with a blower cleaned that up pretty well. To my surprise, instead of a start capacitor I found a full-wave bridge rectifier and brushes, so this mower feeds rectified but unfiltered AC to a DC motor. Got the motor out today. Tomorrow I'll take the bearings out and start looking for replacements. I'm starting to be a little hopeful about this mower.

Interesting that they made the cover so hard to remove that a lot of users will never bother to try cleaning the dirt out of the insides. Got to be bad for the motor. Planned obsolescence I reckon.

 

[StarTech]

The top bearing is not ball bearing.

PN 242735-00



PN 70055-00 Lower Bearing superseded to 070055-00 is a ball bearing. The bearing is a 9502H bearing according to images which should be the 99502H bearing.

 

[the.doc]

The top bearing is not ball bearing.

Correct again, and it looks OK

PN 70055-00 Lower Bearing superseded to 070055-00 is a ball bearing. The bearing is a 9502H bearing according to images which should be the 99502H bearing.

So I should look for 99502H? Maybe find it locally? I see a lot of those on Amazon. Not particularly expensive.