Welcome to the DoItYourself Forums!

To post questions, help other DIYers and reduce advertising (like the one on your left), join our DIY community. It's free!

1990 Lawn boy Model S21ZSNA


texastech1's Avatar
Member

Join Date: Sep 2008
Posts: 3

09-18-08, 05:47 PM   #1  
1990 Lawn boy Model S21ZSNA

My vintage lawn boy seems to lost be loosing it self-propulsion.

I've noted that only the left wheel is being turned by the transmission. I don't know if they are both supposed to or not.

But obviously something is not right in the transmission.

Any ideas? Or should I just say last rites over it and buy another one?

 
Sponsored Links
30yearTech's Avatar
Member

Join Date: Oct 2006
Posts: 1,176
TX

09-18-08, 06:45 PM   #2  
If the only problem is that just one tire is pulling, then I think you can fix that. If the transmission is slipping however then you might want to give it a little thought.

The wheel that is not pulling probably just has a sticking or stuck key in the axle that engages the drive gear. Remove the wheel and then the drive gear, in the axle you will see a slot and in the slot there is a small key with a spring underneath. There is most likely dirt and build up causing the key to stick. Clean and lubricate with a light oil or WD40 so the key is free, then reinstall gear and wheel. Pay special attention to the gear when you remove it and reinstall in the same direction. If you flip it around it will not engage the gear in the forward direction.

Now if the transmission is slipping, you probably will need a clutch disk kit and that's going to run around $150.00 just for the parts, and the transmission has to be completely disassembled to repair.

 
texastech1's Avatar
Member

Join Date: Sep 2008
Posts: 3

09-19-08, 06:11 PM   #3  
It Works

Posted By: 30yearTech If the only problem is that just one tire is pulling, then I think you can fix that. If the transmission is slipping however then you might want to give it a little thought.

The wheel that is not pulling probably just has a sticking or stuck key in the axle that engages the drive gear. Remove the wheel and then the drive gear, in the axle you will see a slot and in the slot there is a small key with a spring underneath. There is most likely dirt and build up causing the key to stick. Clean and lubricate with a light oil or WD40 so the key is free, then reinstall gear and wheel. Pay special attention to the gear when you remove it and reinstall in the same direction. If you flip it around it will not engage the gear in the forward direction.

Now if the transmission is slipping, you probably will need a clutch disk kit and that's going to run around $150.00 just for the parts, and the transmission has to be completely disassembled to repair.
Thank You..most excellent 30 Year Tech / Moderator. I cleaned and lubricated the key and it works quiet well!

 
30yearTech's Avatar
Member

Join Date: Oct 2006
Posts: 1,176
TX

09-19-08, 08:13 PM   #4  
Thats Great!!

Glad that's all it was. Those old Lawnboy mower are great units, but they can be expensive to repair with some models.

 
texastech1's Avatar
Member

Join Date: Sep 2008
Posts: 3

10-17-08, 08:19 PM   #5  
1990 Lawn boy Model S21ZSNA

I'm Back...I wrote last month about my lawn boy's lack of self-propulsion & it worked pretty well a couple of times after addressing the sticking key in the axel. However, it is now decidedly exhibiting symptoms of a slipping transmission. Where can one obtain a clutch kit? All of the sites that I've looked at sell the parts al a carte?



Posted By: 30yearTech If the only problem is that just one tire is pulling, then I think you can fix that. If the transmission is slipping however then you might want to give it a little thought.

The wheel that is not pulling probably just has a sticking or stuck key in the axle that engages the drive gear. Remove the wheel and then the drive gear, in the axle you will see a slot and in the slot there is a small key with a spring underneath. There is most likely dirt and build up causing the key to stick. Clean and lubricate with a light oil or WD40 so the key is free, then reinstall gear and wheel. Pay special attention to the gear when you remove it and reinstall in the same direction. If you flip it around it will not engage the gear in the forward direction.

Now if the transmission is slipping, you probably will need a clutch disk kit and that's going to run around $150.00 just for the parts, and the transmission has to be completely disassembled to repair.

 
30yearTech's Avatar
Member

Join Date: Oct 2006
Posts: 1,176
TX

10-18-08, 08:25 AM   #6  
Toro / Lawnboy 684684 is the part number for the disc kit.

http://www.jackssmallengines.com/sea...x=0&sa.y=0#204

Here is one place you can find it. With the part number, you might want to do a little research on the web and see if you can find a little better deal, as this is an expensive part.

Best of Luck....

 
Search this Thread