Single Stage Blower Broken Chain

[jeff lary 171]

Hello all been a long time since I made a post I think.

Tonight while blowing out a couple inches of fluffy snow we ( the 312-8 and I ) had an issue. There was a large loud bang and lots of sparks,... then I shut her down.

 The drive chain broke and wadded up between the sprocket and the frame of the bearing housing. She (the chain) is toast I am not sure if it is the1995 original chain... or maybe the second chain? I think maybe it's the second one. Anyway a third chain is in the future for the old girl. I called the dealer I bought the tractor from and he will have to order one for me , will have it next Monday $ 35.00.

  I thought that maybe I ought to buy new sprockets as well. I found out that the sprocket that goes on the auger is apparently part of the auger ,as in one unit. So I guess it will be just the chain for me for now. I think the sprockets would benefit from a toss in the junk heap just based on ,..well I will be right in there why not install new now?. But if I have to buy an auger ( cannot imagine the cost of that) I will just get by with the chain. The sprockets still have some life in em so for now I guess they will live on. 

[shallowwatersailor 3,213]

If you have a farm supply, decent hardware store, or TSC nearby, you should be to buy 10 feet of #40 chain for about $20.00. I have a 5xi single stage snowthrower and it is 32 links long. I can get two chains out of the 10 feet.

[jeff lary 171]

Yes I am sure you are correct I actually thought about doing something like that then I got lazy and just called them up.

[squonk 40,999]

I would at least replace the idler sprockets. If they are original, it is time. You can also buy a sprocket for the auger cut off and weld on a new one.

[Kurt-NEPA 755]

Check that auger sprocket.  If it is toast, there are options to a new auger.  You can buy a new sprocket, cut off the old one, and then have the new one machined to fit the auger and then get it welded in place.  I've done it myself, but I have the equipment.  It was a <$50 repair for me.

[jeff lary 171]

He, (the dealer) kept saying idler sprockets ? he had me confused. There are two sprockets that I was talking about. One is " up top" on the drive shaft and the other is on the auger shaft itself. I would have never called either of these idler sprockets? Am I missing something? Is there a "tensioning " sprocket just up from the auger ?maybe that is what he meant? I would have to walk out and look at it and that aint gonna happen tonight ha ha I am down for the night.

[jeff lary 171]

Sorry if that sounded kind of crazy but I am in my chair after a long day of driving in the snow. Almost 400 miles of following petrified drivers all white knuckling it , it gets on my nerves ha ha,. I am tired and trying to picture the blower internals and drawing a blank kind of. He did say he stocked all the sprockets so if I decided to get them after all he had them there on hand.

[WVHillbilly520H 10,373]

There's 2 idler sprockets and the drive shaft sprocket which can all be easily found  and replaced I sourced mine from the "Big Bearing Store.com" as well as the roller chain like $50 total or TSC which is where I got the large auger sprocket that I bored out at work in the lathe ,Jeff.

[jeff lary 171]

 

 I got ya yes there are 4 sprockets I guess not 2 I remember the 2 idler ones now that I see your photo. Thanks for that by the way.

55 minutes ago, squonk said:

I would at least replace the idler sprockets. If they are original, it is time. You can also buy a sprocket for the auger cut off and weld on a new one.

Yes I could do that I guess I did not know it was welded on .

kind of a poor design it should be on a collar and set screwed onto the auger shaft I would think. This summer I will maybe do a rebuild with bearings and auger sprocket.

 When I go to get the chain I will also get the 2 idler sprockets as well. I had been at the end of chain adjustment for a long time sum due t chain stretch and some no doubt due to worn down idle sprockets.

Edited February 2, 2017 by jeff lary

[Kurt-NEPA 755]

I'm trying to place two idler sprockets. I can't see it. From my memory, there is a drive sprocket on the jack shaft, a driven sprocket on the auger shaft, and an idler sprocket on the tensioner.  If I were doing a rebuild, I would replace the drive sprocket, idler sprocket and the chain.  I would leave the auger shaft sprocket alone unless it had significant wear.  I would also replace the auger shaft and jack shaft bearings as well as the belt idler.

[jeff lary 171]

I will look it over closer soon to see what it needs.

[Kurt-NEPA 755]

I stand corrected.  I just took a look at my single stage.  There are two idlers.  Sorry.  Just old age creeping up on me.  They say memory is the second thing to go.

[shallowwatersailor 3,213]

Just to point out a difference in versions of the snowthrower. On the 5xi #79365 Single Stage Snowthrower, there is only one idler. Although the belt dive is different, the chain drive portion is the same (or similar) design.

[jeff lary 171]

So I am at work now but I have been thinking. I think I will see if they have the "jack" ? shaft bearings the one on the belt end and the one on the Sprocket end. I will also get the idler sprockets as well as the new chain. When the chain failed it broke the plastic safety guard where the chain is on the jack shaft up top. It also bunched up and ripped the rectangular opening where the chain leaves the jack shaft and enters the blower housing. So I suppose I should try to do something there to make that look a little better. I am in hopes that my owners manual shows the chain routing on the sprockets too. I can guess a little by looking at the photo Hillbilly posted but I cannot clearly see for absolute sure.

Edited February 2, 2017 by jeff lary

[jeff lary 171]

I found a photo of the chain routing I believe. I just goggled chain routing and a previous Red Square person had posted this.

[WHX?? 48,717]

That is correct routing. TSC will have everthing you need except possibly the drive sprocket but may have them also. Motion will have them if not 40B14F 7/8 finished bore, #40 chain, 14 tooth. .I believe TSC may have the prelube bearings as well.

 

another recent thread where we were discussing  the bad auger sprocket dilemma

 

Edited February 2, 2017 by WHX9

[jeff lary 171]

Here are a few pictures, I have had the old dealer gather up the stuff but I will record all the information in the above post that is good stuff to know. I wonder if it is possible to put on a sprocket in the wrong position? What I mean is the chain may be in one sprocket perfectly but the chain rollers may end up on top of the next sprocket's teeth? I wonder if they are indexed by the use of a keyway ?if not I guess I can install all the sprockets and the chain then when everything is meshed well I can make the set screw connection to the shaft. You can see in the pictures where the plastic guard got broken and the slot for the chain to pass through the housing got torn . The entire chain ended up wound up in a gob right where it normally pass's through the housing thus tearing the housing some.

one more photo well..... I guess not , I am not allowed to up-load any more. Now is that for this post or forever?

Edited February 2, 2017 by jeff lary
spelling

[pfrederi 17,629]

Chains are not supposed to be super tight so i doubt :"indexing" is an issue.  also the lower idler is moveable to adjust tension

[jeff lary 171]

yes I am sure I wont be an issue just thinking out loud ,...or via key board I guess.

[WHX?? 48,717]

Sprockets look fairly decent yet. sounds like you may just need new idlers & chain. Clean up around where the chain ripped up the housing and take off the guard. Mine are all broke off. The chain should have a master link in it. You shouldn't need to take anything else off if your pre-lube bearings are good.

 

This will cure your pic posting problems as well.

 

[jeff lary 171]

yes I agree on sprocket shape. The tops are still slightly blunt not worn to a point. The bearings feel good as well really about 1/16 up / down play at the shaft ends . With new it may be zero play but I would have to change them to see if there is a marked  difference. I will def change the idler sprockets and bearings and we will see about the rest at that time. 

[WVHillbilly520H 10,373]

Those idler sprockets are "sealed" and in my opinion cheaply made vs the jack shaft and auger sprockets spin them by hand checking for roughness and noise and when I refurbished mine the only sprocket keyed is on the jackshaft and the welded auger as you pull the chain through its routing over the teeth it will time itself till you have the chain linked back together then adjust the tension idler start it up and spray some chain lube while it's running, blow some snow then check and readjust tension as the the new chain will stretch once it's used the first time,  just my experience, Jeff, oh BTW I used a marker and made a chain routing diagram on the wing of the drive side.

[jeff lary 171]

Thanks good artistry as well ! Yes the idlers look cheep. I think I changed the chain a few years back but all sprockets are original. I use chain and cable lube and grease the bearings regularly as well. I find that bar and chain oil works well on the chain too. I have a pump oiler and have the boy "bump" the pto while I douse it in B&C oil. I use that red spray can lube / protectant / rust preventer? ...name escapes me now, (They also use it for under coating ) on the chute and auger for snow release ,.....Fluid Film. there that's the name. I think I may lengthen the idler adjustment slot while I am in there... maybe we will see probably a full size not worn sprocket will be a pretty big help.

[pfrederi 17,629]

Motor cycle chain lube

Chains do not stretch they or the spockets may wear  making them loose but they do not stretch

Edited February 2, 2017 by pfrederi

[jeff lary 171]

ya ok