Chain keeps coming off snowblower

[Kschyf]

Hi all, I am new to the forum. I have a b2660 with a front attached snowblower. The blower started running rough and the chain came off twice today. When I got in to fix the first time, the set screws for the sprocket on the auger shaft were loose, so I realigned, tightened them and put the chain back on. But when I went back out to finish the yard, it started making quite a noise again, and the chain quickly came off again. There appears to be a little play in the auger shaft and I can push it forward/backward slightly. What keeps that shaft from sliding forward/backward? Could that be my issue?

 

[mcfarmall]

I suggest watching the chain in question while the blower is operating at the recommended speed. You might have to employ the services of a helper to sit on the tractor while you watch what's going on with the chain. Sounds like misalignment and insufficient tension could be your problem. Is the movement in the auger shaft axial or radial?

 

[Kschyf]

thanks for the quick reply. The movement is axial and I’m not quite sure what should be preventing that axial movement. Watching the chain in motion is a good idea. I’ll watch it tomorrow eve when I’m back at it and let you know what it’s doing.

 

[kubotasam]

Is the snow blower a model B2660 ?
I don't think they make a B2660 tractor.
If it is a B2660 blower and the shaft that the large sprocket is on is moving back and forth check to see if the small gearbox in the front is securely mounted and not able to move. If the gear box is mounted solid check to see if the shaft moves in and out of the gear box. If it moves you have problems in the gearbox and also probably the bearing that is behind the impeller (between the impeller and the large sprocket). The Gearbox will be the expensive repair.
The parts diagram shows a roll pin and a set screw holding the sprocket to the shaft could the roll pin be missing or sheared off?

 

[Kschyf]

Whoops, sorry, the tractor is a bx2660. The sprocket has two set screws which were tight each time a started out. Tomorrow I’ll post the model of the blower and a picture of what the bearing and sprocket area looks like in case someone sees something obvious I’m missing.

 

[kubotasam]

Whoops, sorry, the tractor is a bx2660. The sprocket has two set screws which were tight each time a started out. Tomorrow I’ll post the model of the blower and a picture of what the bearing and sprocket area looks like in case someone sees something obvious I’m missing.

So I am guessing the snow Blower is a BX2750.
If it is, it is very similar to the B2660 snow blower I was describing in my previous post. Checking for play where the impeller shaft goes into the gearbox is still important.

 

[mikester]

Maybe start by adjusting the chain tensioner...

 

[SidecarFlip]

Depending on how old it is and how infrequently you lubed the chain, it could very well be stretched out and the sprockets worn out that is causing the chain to jump off. The drive chain is a high wear point that people in general never oil.

 

[DustyRusty]

While looking for something else today, I came across this thread, and now is the time to get your snowblower ready for the winter. I suggest lubing the chain with a chain saw bar oil since it sticks well in cold weather. Also, remove the chain cover, and check the condition of the chain and sprockets. Check all set screws, and if you find any loose, clean them and use some Locktite Blue on them, so they don't come loose when you need the blower the most, while snow blowing. If the chain is loose, you can tighten it by loosening the 2 outer bolts on the side of the chain compartment, and pushing down on the housing with some taps of a hammer. I used my snowblower for 15 years and it had a lot of hours on it, and I never needed to replace the sprockets, because they were always well lubricated.
Also, keep the tools necessary to change a shear pin with you while blowing. Saves a lot of time rather than having to go back to the garage for a broken shear bolt.