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PhanDad

Going Full Engine RPM with Some Guarding - Pics

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PhanDad
I’m running an older Simplicity snowthrower model #990519) on my Sovereign GTHL. The effective diameter of the electric PTO driven pulley (where the belt runs) is 5 1/8” and the effective diameter of the design driven pulley is 4 1/8”. If the stock driven pulley were used, the snowthrower would run about 25% faster than design. So I installed a larger driven pulley to reduce the speed back to design. The problem is the belt guard that surrounds the driven pulley will no longer fit. The result is the belt hopping off the driven pulley when the snowthrower is “shock loaded” with sliding snow, etc. I’ve been living with the problem for years when the thrower was mounted to my 12HP Homelite (along with the “jury rigged” idler assembly). But now I have 16 HP :D – so I was thinking, maybe I should run the engine at 80% throttle and install the stock driven pulley with guard. (The thrower will be at design RPM) Should I run the full engine RPM setup or the belt guard? All thoughts and opinions appreciated. Of course the best solution would be a belt guard for the larger driven pulley, but I don’t have the capability to do that myself. :( Dan, you got me thinking today - so I messed with some fingers and the original guard, but couldn't make it work, so I abandoned that approach. The larger pulley is a somewhat tight fit, so I adjusted the shaft housing so the back of the driven pulley is about 1/8" from the thrower housing. I added a piece of wood with grooves to the bottom of horizontal attachment plate to close up the gap on top of the pulley. And I added a finger on an extension for the bottom of the pulley (Still can improve this one's location). See the pics below:

It's kind of crude, but hopefully effective. May get to find out tomorrow depending on what falls from the sky. Sounds like the Phila area is going to be right on the snow/rain line. If this doesn't work, then I guess the next option will be to follow Dutch's suggestion and give the local metal shop some business.

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rokon2813
Bill I have a pile of the wire type belt guides of other brand tractors. If youd like I'll mail you a couple long ones to bend and twist and reshape to play with. I wouldnt go to slower engine rpm as that big old briggs is designed to run wide open under load. Might be okay since your running the blower only in cold weather but no point in hurting the engine after all the fine work you've just done. Another thought, have you tried more spring tension to keep the belt tighter and maybe it wont jump?

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Dutch
Bill, If your OEM belt guard is the full type that uses a clamp on the shaft housing, it's not hard to make one. Just buy a piece of flat stock from Home Depot or Lowes. Place two 2x4s on a heavy bench or even the floor. Bridge the 2x4s with the flat stock and keep moving it as you hit it with a heavy hammer. Before you know it, you'll have the proper curve. Then weld the new guard to the old clamp arms. Better yet, any metal shop will roll you a guard in a few minutes for next to nothing.

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rokon2813
Bill, I dont think the finger needs to be down there. If you could rebend a couple and get them so they are positioned about 1/8 inch from the pulley right where the belt and pulley come together, and on the other side where they seperate again. My guess would be the most important one is where when running the belt enters the pulley. That would be the point where, when the belt bounces it catches the edge on the pulley and rotates itself right off the pulley. What the guard or finger needs to do is guide the belt into the pulley groove when the belt is loose. Hope that makes some sense...

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roma3112
Bill I had the exact same problem this past snow storm a week ago. Origionally my blower was on my 3112h then i got a new sovereign and put the blower on that, in the process I had to change the driven pulley to a larger one. Well as you said the old guard wont fit, i got by for a season with a piece pf rod on the underside of the pulley, but this past week with the 24in plus of snow we got in Boston the blower kept poppin belts. What i did was get a small piece of steel rod bend it into an L shape, take the short portion of the L and weld it onto a bolt (with threads all the way up). What i did next was plan a spot for a hole where it would meet the belt/pulley arrangement. Having the threads helpes me adjust the hight of the guard as to not contact the belt too much as to promote friction and burn out the belt. This seemed to work just fine for me, and if you dont have a welder you could bend a piece of rod and thread it?? Hope this helps. john b

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UCD
I have had 4 different blowers from 4 different years/models on my tractor. The latest one from 1999, none of them have had a belt guard just a belt stop like this one. I have never had a problem of the belt comeing offf from the driven pulley.

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