Abby’s Guide > Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) > Discussions > what size pulleys
Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions |
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josjay
Joined: Feb 22, 2011
Points: 19
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what size pulleys
Original Message Feb 23, 2011 4:18 pm |
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what size pulley should iput on 305cc engine there is a 51/2'' pulley on blower .it is a 36' cut blower for a lawn mower but i am modifying to go on atv .its a single stage so i want to get most power i can out of it.any help would be appreciated thanks..
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josjay
Joined: Feb 22, 2011
Points: 19
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Re: what size pulleys
Reply #5 Mar 5, 2011 6:40 am |
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tried a 4 inch pulley on engine today seemed better than 6 inch it seemed to blow snow not too bad but not throwing it very far maybe 4 or 5 feet.should i try a 3 inch or smaller pulley will this help throw snow farther....thanks for info so far.
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jrtrebor
Location: Michigan - 3 hours north of Chicago on the lake
Joined: Feb 10, 2010
Points: 539
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Re: what size pulleys
Reply #6 Mar 5, 2011 8:19 am |
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tried a 4 inch pulley on engine today seemed better than 6 inch it seemed to blow snow not too bad but not throwing it very far maybe 4 or 5 feet.should i try a 3 inch or smaller pulley will this help throw snow farther....thanks for info so far. Stepping down from a 4" drive pulley to a 3" will slow down the auger RPM. So, no the 3" pulley will not "help throw the snow farther" In your first post you said that The engine is a 305cc. Is that the size of the ATV engine? And is that engine driving the blower using some type of PTO shaft or belt? Or do you have a separate 305cc engine mounted somewhere driving the blower? Is the auger shaft on the blower being driven or spun by a chain and sprocket? Does the blower have a right angle gear box on the back of it? With a shaft that has a gear on the end which drives a chain, which drives another sprocket that is mounted on the end of the auger shaft? It's rather hard to give any advice without knowing what type of setup you have. What brand or make and model is the blower you're trying to use. It's also very important to have some idea what RPM the engine drive shaft is spinning at. It's normally around 3600 on most walk behind blowers at full throttle.
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josjay
Joined: Feb 22, 2011
Points: 19
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Re: what size pulleys
Reply #7 Mar 5, 2011 5:59 pm |
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you are right on with what i got. I have a 305 CC BnS engine and a 5 1/2 inch pulley with a sprocket running the chain for auger on bottom. On top I have a 4 inch pulley on engine separate from ATV. Throws snow only 4 to 5 feet. Any more help would be appreciated thanks...
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josjay
Joined: Feb 22, 2011
Points: 19
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Re: what size pulleys
Reply #8 Mar 5, 2011 6:04 pm |
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sorry i forgot to say auger is driven by chain and sprockt would it make any difference to change that part of it.thanks
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josjay
Joined: Feb 22, 2011
Points: 19
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Re: what size pulleys
Reply #11 Mar 6, 2011 9:09 am |
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ok this is what i got a 31/2' pulley on engine with a belt to a 51/2' pulley on shaft. at end of shaft there is a 2' sprocket and a 6' sprocket on auger driven by chain there is no gear box . it seems to throw not bad but only about 4 feet would like to throw farther.any help is appreciated thanks.
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jrtrebor
Location: Michigan - 3 hours north of Chicago on the lake
Joined: Feb 10, 2010
Points: 539
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Re: what size pulleys
Reply #13 Mar 6, 2011 10:56 am |
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There are a lot of factors and number calculations that go into getting things like this correct. Finding out what brand blower you have and what it was made to go on would be a big help to you. Knowing what speed the auger was designed to spin at is an important number. If you know what brand blower you have and or what the model is. It would be to hard to get some information on it. If you use the 900 RPM speed that Bill H posted and the pulley and sprocket size you posted. It could go something like this 2700 RPM shaft speed X 2 (sprocket size) = 5400 / 6 (auger pulley size) = 900 RPM (Engine crank speed) 3600 RPM X 3.5 (engine pulley size) = 12600 / 5.5 ( pulley size) = 2290 RPM That 2290 RPM speed is to slow you need 2700 to have an auger speed of 900 RPM So if you decrease the "driven" pulley size from 5.5" down to 4.5" you get. 12600 / 4.5 = 2800RPM If you then recalculate that would work out to an auger speed of 933 RPM. But all this depends on the 900 RPM auger speed being what you need. What you're trying to do, is do able. But you have to know where you're trying to get to, before you can figure out how to get there. I think you may need more information to get things right.
This message was modified Mar 6, 2011 by jrtrebor
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