W5021 SC - broken Self Propelled

[JohnMcClain]

I'm a new member, as I recently obtained this mower from the son of a neighbor that bought it new before he died 21 yrs ago. Finally removed all varnish from carb and have it running well, but the self propel won't engage.
The drive shaft only turns if I push the mower.
I'm surprised as this mower looks like it saw little use before being left in the garage over 2 decades.
I ordered a new grass catcher bag & frame for $165 (b/c the son had already thrown the original bag away) and learned that the parts guy at my local Kubota dealer, has 2 similar mowers that also had non-functioning self propell, but he doesn't know why.

Are these Kubota push mowers known for having frequent problems with the self propelled function?

What does it cost for part(s) to repair and is it worth it?
If repaired, it is likely to fail quickly again?

Does anyone have an exploded view drawing of the gearing, showing how the engine drives the shaft?

Also, can anyone help with the age of this mower, based on my S/N - 117869 ?
Thx.

 

[Daren Todd]

Did a quick Google search for your mower. Of all places, I found a parts diagram at sears obviously there is some issue with the transmission. But you'll have to tear into it to see what's not working.


http://www.searspartsdirect.com/model-part/w5021sc/1320/1500600/00048559/00012.html

On the two self propelled mowers I've had over the years, I've found it was usually foolish and simple as far as why it didn't work. One was a worn sprocket. And the other was a piece broke where the cable attached to the rocker to engage the drive when you pulled a handle.


Good luck and post lots of pics. Most of us haven't seen a kubota push mower

 

[RCW]

These walk-behind mowers have shown up on this forum several times.

I bought one 25 years ago from Sears. I guess that explains the parts connection, Daren. It was a very well-made mower, and did a hell of a job.

Mine wasn't self-propelled and ethanol gas got it.

Had an old scrap woodstove out front FREE - kid that stopped for it wanted help loading it!! That was ballsy in my book.

Told him I'd help him load it, if he took the mower too!!

 

[North Idaho Wolfman]

John,
Go to Kubota.com and you can see all the parts.

The drive shaft is drive by a gear on the camshaft, first, pull the drive shaft that goes out from the motor and check the splines.

 

[jcansler]

I have a W5021 SC that was working great and it suddenly quit pulling, the driveshaft stopped turning. I took the engine apart and discovered there was a cotter pin that had broken, that is all that stops the driveshaft from becoming disengaged from the drive gear.

Once the cotter pin fell out (or broke) it got chewed up and mixed into the oil, ruining the bearing. I took the engine completely apart and rebuilt it, putting a new cotter pin on the driveshaft. It is still running fine today and gets used occasionally.

It was hard for me to believe that a cotter pin is all that keeps the driveshaft properly engaged and the damage that the broken cotter pin caused.

You can check the play in the driveshaft and see how much play there is, maybe this will help you diagnose if this is your issue or if it is something else.

If I remember correctly it is very simple to tear down and rebuild the engine if it is needed. I hope this helps...Good Luck...

Joe

 

[JohnMcClain]

Thank you all.
I will take it apart and look for a missing cotter pin. Hopefully not a worn gear.

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