SB1184 snowblower issues?

[orlo]

Hi:

At the end of January 2010 I traded in my 3720 for a 4720 and got an SB1184 on the rear.
Here in the NorthEast kindom of VT we never really got any significant snow after that. I tried it out for literally 2 minutes on 4 inches of snow - Seemed ok.

First time using it this year (I may have tensioned the chain and lubed it), I got about 50 feet, hear a bang, backup and see the #60 chain sitting on the ground. Busted side plate.

Ok, I figured it was a defective chain. Got a new master link, etc. Put it on but I couldn't tension it - Would seem tight, then very loose. Looked and I had about 1/4" deflection in the small sprocket on the shaft from the gearbox (Shaft was bent). Ok. Chicken or the egg? Was it the bent sprocket that caused the chain to break, or did something jam the chain or get between the chain and the sprocket (Jumped a tooth maybe). Note that the shear pin on the shaft near the gearbox was NOT sheared.

Anyway, I figured it would take a lot of force to bend a 1-1/8" steel shaft 2.5" from the end - I also figured that if there was that much force the sheet steel holding the bearing on the end would have bent. So I guess I concluded it was always that way.

Ok, new shaft ($40+, new chain just in case. Put it all on, etc. Seems ok. I hear a small bang and the shear pin went. Oh well, it was probably weakened before. Got a new one, etc. Used it the rest of the day. Noticed when using it that the chain seemed very loose.

Looked and it indeed was. Looked at the shaft and it looked like it had a very small deflection in it (not like the 1/4" it was before).

Question:

Has anyone else had issues like this with an 1184? If so what caused them? I can't imagine Ice getting in the chain (and crushed by the sprocket) would cause such an issue.

 

[orlo]

I did the best I could to straighten out the old shaft on a 20 ton press last night. Is reasonably straight. I'll keep it as a spare.

I was hoping somebody had experienced the same thing and it was some sort of setup issue but maybe not.

 

[jester156]

this is my first season on my 1154 and I have no complaints so far. given the same style of blower as the 84, I will keep an eye on my bar and see if I notice any deflection over the season. so far, its worked as advertised :thumbsup:. just too dam efficient resulting in lower seat time.

 

[Dutch445]

Orlo, are you aware of any rocks? That's more likely
to bend that shaft than some ice running thru the chain
and sprocket.

Can you remember when you adjusted the chain last
summer if you rotated the shafts all the way around?

 

[orlo]

I'm sure at the beginning of this season I lubed (and maybe adjusted the shaft). I would have turned it to lube it, but at the time not knowing what I know now I'm not sure I would have turned it other than a little bit back and forth to check the slack.

I'm not aware of any large rocks. There is gravel and crushed rock but it would have to 'stick' to the chain to get between the chain and the sprocket. I suppose it could have even been a small piece of wood. Also, both when the chain came off initially, and when I sheared the bolt I looked for anything on the ground/area and found nothing. Granted the auger spinning down after shearing the bolt (or snapping the chain) could easily had enough momentum to put whatever it was into the blower (Which was still spinning as it's before' the auger shear bolt).



I may look into a spring loaded tensioner rather than the fixed bolt. That would allow some debris to ride under the chain without putting enough stress on it to bend the shaft.