Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

Hi all - please help an ignorant fool with his first snowblower.....  I've inherited a Yamaha 2 stage machine.  It's about 15 years old and in fantastic condition.  The engine runs great, and until the first time I used it, so did the auger.  After probably going into a pile of snow too fast, the auger has stopped working.  Nothing happens when hold the auger handle down.  People have said that I've more than likely busted a shear pin, but I can't seem to find a broken one.  Currently, when the machine is off, i can manually turn the auger, which in turn, rotates the impellar.  If I have broken a schear pin, would this be happening?

Thank you!

I get the feeling you may have mixed up the terminology since the impeller ( throws snow ) is connected to the auger ( moves snow into the impeller) via a worm gear. This is unidirectional. You can turn the impeller and the auger rakes will move but you can't turn the rakes and have the impeller move. If you try to move the auger rakes hard enough you might break part of the worm gear.

The auger rakes are attached to a hollow tube that the auger drive shaft is inside of. The hollow tube is connected to the drive shaft by 2 or more shear bolts that fit through holes in both the tube and the shaft. They are a special type of hardened bolt and are designed to shear when the load on the rakes is too high. They are a mechanical fuse that tries to stop damage to the rest of the drive train. On most machines there are two sets of rakes one on each side of the gear case. There are some that have four sets of rakes, two to a side. Each set will normally have one shear bolt.

Here's how to check it out:

1. Turn machine fully off, fuel cutoff ( if you have one), throttle off, spark plug disconnected, ignition switch off;
2. Check to see if any of the auger rakes will turn, use a stick, if so then one or more shear bolts need to be replaced;
3. Using a stick check to see if turning the impeller causes the rakes to turn, if it doesn't then either the drive shaft is broken ( unlikely) or the gears in the gear case are stripped ( more likely but unlikely as well);
4. Open up the cover just in front of the engine and check the pulleys, the front one is for the impeller/auger system. The belt could have come off or broken. Fix as necessary, I posted a long and windy description of how I do this, try searching for it. I've heard that the Ariens manual give a good description but haven't read it. I think its available online.
   

Given that you can turn the impeller and the auger turns and assuming that you can't turn any of the rakes then its probably the pulley.

I did a bit of searching and you can find a set of Ariens' manuals here. It gives the basic idea but doesn't seem to mention any nice "tricks". If you can find manuals for your specific machine it would probably be best.

One thing I found handy was to run a line from the handle bars to the auger housing, hooking it onto the top edge of the housing. By varying the tension on the line you can control how the two sections open/close up when removing/replacing the bolts. A ratcheting tie done strap works best. I also put blocking under the wheels to lift them up and stop them from moving back an forth. I plan to make something that will do the same thing by holding up the machine by the axle.

I did some searching and found the procedure that I posted here.

Take the shear pin out for inspection. 

I once had one break and both ends of the bolt were stuck in the auger, despite it not being connected to the shaft.

Small chance, maybe, that when you spin the auger it that it's catching on a burr of a shear pin and spinning the impeller.

Probably not your issue, but worth the minute to check before operating on the unit.