High revving B&S engine

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  #1  
Old 03-29-07, 05:24 PM
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High revving B&S engine

Hi. Let me first say I know very little about engines, so forgive me if this is a pathetic question.

I have a 3 Year old Craftsman with the B&B 407777 0167-E1. It revs very high (sounds like it is about to take off!) and I have to shut it off. The throttle will not control the engine speed. I am afraid it is an internal issue, in which case it will probably be best to buy another mower, but I am hoping for the best.

Thanks
 
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  #2  
Old 03-29-07, 05:40 PM
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The throttle shaft may be "froze" at wide open throttle due to varnish buildup in the carburetor. Or, you may have a binding issue at the governor/throttle linkages. The best way to check for issues with either is to grab ahold of the throttle arm on the carb and see if you are able to move it at all or perhaps with some minor, spring-related resistance. If you believe you have no trouble here then you need to be concerned of a possible internal governor issue. Is this, perhaps, the first running attempt since a winter hibernation?
 
  #3  
Old 03-29-07, 07:08 PM
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This was actually a problem that occurred at the end of last year. I am just now getting around to looking at it.
 
  #4  
Old 03-31-07, 08:01 AM
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Again, it's likely a varnish/gum issue in the carburetor, can you manually move the throttle arm on the carb? If you, indeed, have varnish, you'll need to disassemble and service the carb.
 
  #5  
Old 03-31-07, 01:55 PM
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Yes, I can manually move the arm. I looked at it and I really could not figure out how to get to the carb to clean it. Once again, not much knowledge in this area!
 
  #6  
Old 03-31-07, 02:01 PM
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I can manually move the throttle and it does control the engine speed, but when I use the throttle cable, it has no effect. Would this still be a varnish issue? Sorry if I was unclear.
 
  #7  
Old 03-31-07, 02:42 PM
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If you cable will not move the arm then you would have a frozen cable which needs to be freed up or replaced. You can try a little WD-40 on the cable to see if that loosens it up.
 
  #8  
Old 03-31-07, 02:43 PM
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P.S. You could also check to see that the cable is properly attached to the throttle lever. Those plastic throttle levers are notorious for internal breakage. If the lever moves but the cable does not, it's time for a new cable.
 
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