# Old Craftsman Single-Stage with Broken Sprocket



## TommyD (Feb 2, 2014)

Hi All,
I'm brand new to the forum. 

I have a Craftsman Snowblower, model number 536.90490.RA3, that now has a broken sprocket on the shaft coming off of the engine to rotate the impeller. It looks like a powder metal gear held on to the rotating shaft by a set screw, and it is now broken into three pieces, two of which I was able to recover.

This is a single-stage machine, 4 hp, 20" width, 10.5 cubic inch, self-propelled.

I tried searching Google as well as the Sears website for replacement parts, but no luck.

The machine is old, but runs well, so I'd like to fix it...any help is much appreciated!

Thanks!


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## Shryp (Jan 1, 2011)

If you need sprockets perhaps there is a bearing supply place or some sort of industrial supply place local to you that you could try? What about a go kart place? 

Maybe try here.
Sprockets for Go Karts & Mini Bikes | Go Kart & Mini Bike Parts | MFG Supply


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## detdrbuzzard (Jan 20, 2012)

hello tommyd, welcome to *SBF!! *someone said to try a minibike shop and see if they c=have a sprocket that will work


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## Mr Fixit (Nov 19, 2013)

I just happened to have owned one of these Craftsman blower long ago. Built in July 1971. Mine had a clutch assembly on the motor shaft. Likely Canadian regulation required it. When you idled the motor the machine disengaged and the blower stopped. Possibly that has been altered to a new sprocket on your machine?
Original parts was 6 parts and a set screw. Are you interested in the list of original parts?


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## Kiss4aFrog (Nov 3, 2013)

You're going to need the diameter of the shaft, the width of the key and the outer diameter of the pulley to do some shopping for a replacement.


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## TommyD (Feb 2, 2014)

Hi All!
Thanks for the great feedback and sorry for the delay in getting back to you.

Okay, I did some measuring and I think this is what I need:
*3/4" diameter shaft/bore
*1/4" diameter pin
*16 teeth (hard to tell, missing part of the gear, but a decent estimate)
*Gear Diameter: 2" / 1.5"

Attached are some pictures of the machine as well as the remaining pieces of the gear and the pin. It looks like I'll need one of these as well.

Kiss4aFrog - that appears to be the owners manual...can you confirm the dimensions, perhaps? And the chain type - 35? I actually ordered a manual some time ago on eBay, but can't seem to find it. I am recently married, so all of my stuff is being 'rearranged' currently. The gear is on the left side of the machine machine, most outboard chain that drives the auger. I tried finding it on the Sears website, but it is too difficult to zoom in on the pictures and nothing is available


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## TommyD (Feb 2, 2014)

Mr Fixit said:


> I just happened to have owned one of these Craftsman blower long ago. Built in July 1971. Mine had a clutch assembly on the motor shaft. Likely Canadian regulation required it. When you idled the motor the machine disengaged and the blower stopped. Possibly that has been altered to a new sprocket on your machine?
> Original parts was 6 parts and a set screw. Are you interested in the list of original parts?


Yes, whatever you can provide assuming it has a description would be helpful, Mr_Fixit. It doesn't appear that mine has a clutch like you describe - perhaps that is the "RA" suffix that appears at the end of the model number.


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## TommyD (Feb 2, 2014)

detdrbuzzard said:


> hello tommyd, welcome to *SBF!! *someone said to try a minibike shop and see if they c=have a sprocket that will work


Thanks! I'll see if this works once I can confirm what I need...I did a quick search already and it looks like there are options.


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## TommyD (Feb 2, 2014)

Shryp said:


> If you need sprockets perhaps there is a bearing supply place or some sort of industrial supply place local to you that you could try? What about a go kart place?
> 
> Maybe try here.
> Sprockets for Go Karts & Mini Bikes | Go Kart & Mini Bike Parts | MFG Supply


Thanks for the suggestion. I checked it out, but it looks like the gear I need is unique in that it doesn't have a key way...


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## Kiss4aFrog (Nov 3, 2013)

Yup, looks like yours is pinned to the shaft.

It seems it's PN 43397 it show on Sears NLA. I think that's right from what I can see in the parts diagram.
Have you contacted Sears Parts Direct to see if they can cross it over ??
Have you already searched for it ??

You could also try Boston Lawnmower Co. I found they still had no longer available parts for my Craftsman.
http://www.bostonlawnmower.com/


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## TommyD (Feb 2, 2014)

Kiss4aFrog said:


> Yup, looks like yours is pinned to the shaft.
> 
> It seems it's PN 43397 it show on Sears NLA. I think that's right from what I can see in the parts diagram.
> Have you contacted Sears Parts Direct to see if they can cross it over ??
> ...


Thanks for the part number and the suggestions! Can you give me the part number for the pin? It appears that I need this part as well...

I chatted with a Sears representative online, and they confirmed that the part is no longer available with no authorized substitute identified. I also sent a note to Boston Lawnmower as you suggested as I didn't see anything Craftsman related on the website.


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## Kiss4aFrog (Nov 3, 2013)

It's call "Device Link Optical" and it's PN 21768 replaced by # STD316358

The name throws me but it's still available at Sears $2.49 and that seems right and it's for a snow blower, but ???

Model # 53690502 | Parts.Sears.com


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## Shryp (Jan 1, 2011)

Looks like a regular roll pin no? I would think you could just go to a hardware store and get a standard roll pin or shoulder bolt and nut. Maybe try some local go cart, mini bike, lawnmower or industrial / bearing supply places for the gear. Maybe find some place that sells commercial electrical motors for machinery.


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## TommyD (Feb 2, 2014)

Thanks for the information and suggestions, Kiss4aFrog and Shryp.

I will try to find a local place and get their thoughts. Maybe a 15 tooth keyed gear can be modified by a local shop: drill through one of the set-screw holes to convert it for a pin/shoulder bolt. Then I'd be back in business!


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## Mr Fixit (Nov 19, 2013)

My parts list shows that as a jack shaft assembly 1071206. Registers as correct part at Sears com but obsolete. Chain shown 56P.
Could you not drill out a hole in the new 35 tooth sprocket you source for a roll pin? There are sprockets that come in two seperaqte pieces. the variable tooth (36) sprocket then the variable centre part that weld together. 
Shown here.
36 Teeth X-Series Weld-On Sprocket | Princess Auto


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