Snow Model 551 CC Snow Blower

[VinceSMTA]

I think Mud&Grass has some good advice. If there are burn marks on the belt it probably means that something is freezing during operation while the belt continues to turn. From my experience, sometimes it takes a fresh set of eyes to look at it to make sure all is fine...so go buy some beer and invite a mechanically inclined friend over.

 

[rcbe]

Ken - just another thought... that gearbox - is it properly lubed? ck yer manual for any specs on that and then the box's lube condition. If it's poorly lubed, may wanna seize up when under heavy load and heating up... such could quickly burn a belt and then cool right back down before you got the tractor back in the garage... long shot, mebbe - but worth a look.

 

[kruss77]

If there are burn marks on the belt it probably means that something is freezing during operation.

I suspected that too. But everything moves freely and is in correct alignment. The "burn" mark is really just a discoloration of half the backside (non 'V' side) of the belt running the entire outside diameter of the belt. I saw this same thing before when my original belt rolled over on edge a couple of years back. (In that instance, I stopped the blower before the belt was damaged.) My suspicion is that the tensioning spring on the idler pulley has relaxed over time and does not maintain proper belt tension under heavy loads anymore (I lost both belts during heavy snow removal). With such a stiff belt, this could allow the belt to roll over as it tries to twist 90* from one pulley to the next. If that is true, the discoloration on the back of the belt would be caused by friction (as the belt is now riding on edge and not gripping properly) as the backside surface is dragged against the pulley groove. This would also result in a loss of power on the blower without a corresponding loss of engine power (which is what I experienced) as the belt loses its grip on the drive pulley as a result of riding on edge. That makes the most sense to me based upon the evidence. I'll know for sure after I re-tension the idler pulley with a replacement spring and run it again.

... that gearbox - is it properly lubed? ck yer manual for any specs on that and then the box's lube condition.

Suspected that too, but it is permanently sealed and can not be lubricated by the user. Now, that doesn't beam it's not the problem, but it wasn't even warm to the touch when I lost the belt (I had initially thought I hit something with the auger and lost a shear pin, so while inspecting the blades I touched the gearbox and it was cool).

I'll know more after my idler pulley tensioning experiment (which I suspect is the real culprit).

 

[kruss77]

OK, I picked up both an aftermarket Kevlar belt and another CC OEM Kevlar belt. The aftermarket belt (from Tractor Supply) is shown in the photo below. This is the belt I'll be using to test the improved idler pully spring tension rather than risking the more expensive OEM belt. If the aftermarket belt works with the new idler pully spring, I might just keep using it instead of swapping-out for CC belt. In the other photo attached below, the new spring for the idler pulley is on the right . The original OEM spring is on the left.

I'll be installing everything later today and will post pictures once installed.

 

[rcbe]

lookin good - keep us posted.

 

[jimdiesel1]

I had a similar problem, found out why....check the bolt/strap in the auger housing that supports the auger and gearbox. Mine was missing, which allows the auger assembly to drop more under load, since the big pulley for that belt is on the same shaft it would misalign badly. In fact it broke the mounting ears off of the gearbox ahead of that large pulley! I looked for problems for awhile before I noticed, it is easy to overlook.

Since I replaced the supporting bolt through the strap that supports the auger unit (drops from the top of the auger housing to the auger gearbox) I have never had additional problems. It is a fine snowblower in my opinion.

 

[kruss77]

I had a similar problem, found out why....check the bolt/strap in the auger housing that supports the auger and gearbox. Mine was missing, which allows the auger assembly to drop more under load, since the big pulley for that belt is on the same shaft it would misalign badly. In fact it broke the mounting ears off of the gearbox ahead of that large pulley! I looked for problems for awhile before I noticed, it is easy to overlook.

Since I replaced the supporting bolt through the strap that supports the auger unit (drops from the top of the auger housing to the auger gearbox) I have never had additional problems. It is a fine snowblower in my opinion.

Thanks. I'll check that out when I get back to it. It's been over 50* for the last two weeks here in south-eastern Michigan and all of our snow is gone, so there's been little urgency for me to get this wrapped-up. I had to use the tractor for something else yesterday and took the blower off it to make that task easier, so it'll be easier to inspect for those things you've mentioned with the blower off the tractor. I might be able to get back to it this weekend. I'll inspect it thoroughly and report back what I find.

Thanks.

 

[kruss77]

Well, I found part of the problem: sometime this season (probably when the first belt let go) the moveable idler pulley arm got bent -meaning that the pulley itself is no longer aligned with the main drive pulley on the blower. This is particularly important because there is only a short distance between It's bent about 1.25" board making it impossible for the belt to remain on the idler pulley with the PTO engaged. I couldn't see the misalignment with the blower on the tractor (which explains why I lost the second belt so quickly after replacing it -the blower was still on the tractor when I replaced the belt) and it only became apparent what the problem was after glancing at the blower from this perspective. This idler pulley swivels freely around its pivot bolt and can contact the ground without a belt on it. I remember the pulley getting pinched under the tractor when I lost the belt earlier this season and that's probably when the idler arm got bent (shame on me for not assuming an 800lb tractor MIGHT bend a 3/16" thick piece of metal -and conducting a more thorough inspection at that time). Regardless, this may make my theory about the idler pulley spring baseless, but I'll probably go ahead and install the heavier spring anyway. I guess it can't hurt at this point!

 

[kruss77]

This was my 'fix' for this problem:

The root cause of my problem was indeed the bent idler pulley bracket. Knowing that this type of failure was likely to happen again over time, I welded a small length of angle iron to the idler pully arm to prevent it from bending again (even under the weight of the blower). That solved my problem.