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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.

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.

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.




thanks for the help

Rivets said:

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.

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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.

Tiger Small Engine said:

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.

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

this mower runs household AC so no battery.

StarTech said:

this mower runs household AC so no battery.

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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.

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.

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.

StarTech said:

The top bearing is not ball bearing.

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Correct again, and it looks OK

StarTech said:

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.

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

Not 100% sure that the 99502H is the same as the 9502H but makes sense here. Just about any good would have the 99502H bearing as it use in older Murray spindles.

Here is the measurements of the 99502H bearing.

Bearing 99502H, 5/8" x 1-3/8" x 7/16" [ID x OD x H]

Just found the Peer 9502H and the two listed specs matches the 99502H bearings.