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Snow Blower Drive Pulley

9 posts in this topic

ID: 1   Posted

My 42" snow blower doesn't seem to throw snow as far as I think it should. The drive pulley is gray so I am assuming sometime in it's past the original pulley was removed. I am thinking that the replacement is bigger. Can anyone tell me how big it's suppose to be?

Thanks

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ID: 2   Posted (edited)

Bigger Smaller on the thrower would make it spin faster. (I fixed this - just in case someone decides to call me out before reading the rest of the thread.)

The pulley on my 1986-ish 42" thrower is big enough in diameter that the drive belt will not fit between it and the wrapper (auger housing) without some friendly persuasion. :eusa-whistle:

Throwers (single stage) are not blowers. (no fan) If they get the snow out of the way, they're doing their job.

I never expect mine to throw snow into the next county, but it does a great job of launching frozen dog crap about 40 feet. :handgestures-thumbup:

Edited by TT
Human error. = )
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ID: 3   Posted

Ya but TT, the neighbors yard is 45 foot away !

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ID: 4   Posted

On my 79360 42" thrower the pulley is 5.5" with 1/8" clearance to the auger hosing. I can't take the belt off without either sliding the pulley off the shaft or loosening the bolts that hold the shaft bearing next to the pulley, which then gives enough movement in the shaft location to replace the belt. I recall the same clearance on 2 other 42" throwers I have owned so 5.5 must be correct.

I believe a larger pulley on the thrower drive shaft does make it spin slower and if you move the belt to the engine PTO inner (larger) pulley it will spin faster. Manual says use outer PTO pulley for snow, inner for mower deck. However if on the inner PTO pulley, there are some issues with belt hitting the hood side posts and not being in alignment with the lower pulley. If the engine is cranking at full speed 3600 RPM, the auger should be the correct OEM recommended speed. Fast enough for me when watching it at full throttle, especially if the old Crap hits the Fan!! as TT says.

Wyatt

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ID: 5   Posted

Bigger on the thrower would make it spin faster.

Not hard to tell I was thinking of food instead of paying attention to what I was typing. :hide:

Here's my thrower:

416snowcrew009.jpg

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ID: 6   Posted

I am referring to the pulley on the cross shaft. You meant that the smaller the pulley the faster didn't you? I put a smaller pulley on an older 30"?? Wheel Horse blower. Really made a difference. I have a a belt alignment problem as well but that may be related to the gray pulley. I notice that yours is the proper color

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ID: 7   Posted

You meant that the smaller the pulley the faster didn't you?

.............I notice that yours is the proper color

Yes.

Mine still has the original pulley. Wyatt took care of posting the diameter. :handgestures-thumbup: :text-thankyoublue:

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ID: 8   Posted

Note that TT in the photo of his 416-8 has the belt on the inner PTO pulley on the tractor which is a larger pulley, which will make the belt move faster thus making the auger shaft spin faster. Engine at 3600RPM a bigger pulley on the PTO makes the belt speed faster. On the thrower a given a 5.5" OEM inch pulley on the shaft, the shaft speed is set by how fast the belt moves. Faster Belt speed spins the pulley faster. Making that thrower pulley smaller would make it even faster as a smaller pulley would spin faster RPM to keep up with the belt speed. Faster belt speed on a smaller pulley, it would spin faster keeping up with the belt speed. Under a heavy snow load, depending on HP of tractor, the thrower will make the engine work harder with smaller pulley or putting the belt on the larger PTO pulley. Either way the engine has to be enough HP to handle the faster speed of the auger. Smaller pulley on rear tranny drive shaft and larger pulley on PTO makes the whole tractor much, much faster. Same idea.

Look at TT's photo. The inner PTO pulley is roughly the same size as the thrower shaft pulley. So every revolution of the PTO = same RPM for the auger drive shaft. 3600RPM. Of course the chain sprocket is much smaller and it takes several shaft revolutions for the chain to spin the auger 1 RPM. Not sure on the PTO vs Auger speed ratio. I just know that the manual says put the belt on the smaller outer pulley on my C-125 and 312-8. Maybe 12HP is only enough to handle the outer smaller pulley. 16HP can handle a faster speed of auger without bogging down?

To each his own. I have never had issues with throwing far enough to get the snow off the driveway onto the lawn with the normal setup. Here is a link to my 312-8 single stage with belt setup and pulley per OEM manual. Not a problem.

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ID: 9   Posted

It appears from the photo's and description that I have the right size pully. I am using the inner pully which explains the belt alignment problems but I think I am going to speeed up the auger with a smaller pulley. I have a hydro and 16 HP so I do not think over loading the motor is going to be a problem.

As an aside I epoxied the inside of the chute. I am looking forward to seeing how well that works keeping the chute clean.

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