Abby’s Guide > Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) > Discussions > Okay, Stupid Question Time
Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions |
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Richie
 
Bring On The White Stuff
Location: Long Island, New York
Joined: Dec 12, 2003
Points: 562
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Re: Okay, Stupid Question Time
Reply #4 Feb 21, 2005 4:21 pm |
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I don't understand what this surging is, Are you describing the rpm running up above normal? or just rpm fluctuating while the throttle position remains the same? Just curious thanks.
Hi there Mang,
When the RPM fluctuates while throttle position remains constant. When it happens on my snowblower, I'd have to stop what I'm doing, leave the machine at operating RPM but not under any load and wait a few minutes for it to correct itself. Not very convenient in snow conditions. If you try to continue blowing snow during this condition, you'll easily clog the machine. In my case it was caused by the over-leaned EPA non-adjustable carburetor. Some in this forum have not experienced it, but I have on my Honda OHV 5 HP pressure washer, Sears chipper/shredder 8.5 HP Briggs L-head, and my new Tecumseh powered Toro snowblower. Since two of the three are used in the summer, I felt it had nothing to do with the oxygenated fuels. In fact, the manual that came with the Tecumseh engine says that you can use oxygenated fuels and do call out the percentages that are accepted. For this reason, I felt I should replace the carb on the snowblower, which made all the difference. I don't intend to make any modifications to my summer weather power tools.
Richie
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jubol
Location: Dover, De
Joined: Oct 3, 2003
Points: 1558
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Re: Okay, Stupid Question Time
Reply #6 Feb 21, 2005 4:46 pm |
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  Mang , You lose about 2.77% of your HP for every 1000 feet above sea level. You, at 4400 feet you lose about 12% of your engines actual HP. Hope this helps!! Fred 
Husqvarna STE927(11.5HP) snowblower, MTD Pro Series 18/42 Lawnmower, MTD 6.5 HP Self Prop Lawn Mower, Weedeater 1500 Blower, Web Gensis 2000
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Richie
Bring On The White Stuff
Location: Long Island, New York
Joined: Dec 12, 2003
Points: 562
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Re: Okay, Stupid Question Time
Reply #7 Feb 21, 2005 4:51 pm |
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That explains it richie, thanks. I would love to replace my carb, at 4400ft I'm losing some hp, and that dern oxy gas is crap, my blower stumbles every once in a while at any rpm and when I take it up from idle to full throttle even if i do it slow, it nearly dies, I think it's the gas. Is there usually a place to buy non oxygenated gas(for ope) in cities that use it?
Hi Mang,
At that altitude, you may have to purchase an altitude kit that consists of a different main jet. If I'm not mistaken, and your machine is actually set up to operate at sea level, it may require a leaner high speed jet. Less air mean less fuel is needed. It may make the engine run better, but at some point, and I'm not sure if 4,400 ft above sea level qualifies, but the engine will never be able to achieve its optimum power output. I suggest you consult with a local dealer for your machine. They'll know exactly what you need. Hope this helps.
Richie
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Richie
Bring On The White Stuff
Location: Long Island, New York
Joined: Dec 12, 2003
Points: 562
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Re: Okay, Stupid Question Time
Reply #8 Feb 21, 2005 4:53 pm |
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You lose about 2.77% of your HP for every 1000 feet above sea level. You, at 4400 feet you lose about 12% of your engines actual HP. Fred, I just saw your post. He's running too rich a mixture if he's set up for sea level, correct??
Richie
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jubol
Location: Dover, De
Joined: Oct 3, 2003
Points: 1558
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Re: Okay, Stupid Question Time
Reply #11 Feb 21, 2005 5:39 pm |
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Mang, Please read the Richie "Got me hooked" thread on Carbs!! Might help you! Fred
This message was modified Feb 21, 2005 by jubol
Husqvarna STE927(11.5HP) snowblower, MTD Pro Series 18/42 Lawnmower, MTD 6.5 HP Self Prop Lawn Mower, Weedeater 1500 Blower, Web Gensis 2000
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Richie
Bring On The White Stuff
Location: Long Island, New York
Joined: Dec 12, 2003
Points: 562
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Re: Okay, Stupid Question Time
Reply #12 Feb 21, 2005 6:05 pm |
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To rich huh, I guess that's logical, all these carbs are the same on this model no matter where you buy it probably. Maybe that's why it stumbles?
Mang,
It's just a simple main nozzle change that you need. I don't have a nozzle size chart handy. Unless I'm mistaken, all that has to be done is remove the bowl nut/main nozzle under the carburetor, and replace it with the appropriate high altitude version. Funny thing is if you check your engine manual, you'll note that Tecumseh states that the sea-level carburetor configuration is good up to an altitude of 7,000 feet.  I don't know where these guys come up with this stuff. My 50 HP twin cylinder snowmobile crapped out at about 2,000 feet above sea level requiring me to change the jetting while on a trip. It ran very rich, spit and sputtered. Have your dealer get you configured correctly. Let us know how it works out.
Richie
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