Tecumseh 8 HP Snowblower Carb Problem

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  #1  
Old 12-17-07, 11:59 AM
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Tecumseh 8 HP Snowblower Carb Problem

I have a Tecumseh 8 HP powered snowblower that is about 12 years old. I left stale fuel in it a few years ago and it has not run smoothly ever since.

I cleaned and replaced the carburetor but now just to get the engine to run I have to give it full choke and let it warm-up until it sputters then set the choke at . It will run for a few seconds and sputter again then I need to return to full choke. The only way to get the engine to run at all is to constantly switch between full and choke.

I have tried adjusting the fuel mixture screw at the bottom of the carburetor bowl but it does not seem to have any effect.

So far I have,
Removed and cleaned the carburetor.
Replaced the float and O-rings.
Drained the fuel tank and added fresh winter gas with stabilizer.
Replaced the spark plug and adjusted the gap.
Set the idle adjustment screw out one full turn.
Set the fuel mixture screw out anywhere from 1 to 6 full turns.

I am guessing that the fuel mixture is to lean but I cannot figure-out why the adjustment screw has no effect. Any insight into this problem would be greatly appreciated.
 
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  #2  
Old 12-17-07, 12:32 PM
indypower500's Avatar
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Join Date: Aug 2007
Location: new hampshire
Posts: 118
How did you clean the carb? Did you buy a gallon of liquid carb cleaner and soak the carb for at least 3 hours? Did you blow out all holes in the carb with compressed air? Did you install a new carb kit? If not, that is what you need to do. Your problem is passages in the carb are plugged and the needle & seat may have varnish on them. The ONLY way to clear them is to soak the carb in liquid carb cleaner then blow out the passages with compressed air. Varnish is plugging the holes. Spray carb cleaner will NOT do anything to varnish. Spray cleaner is only to clean the outside of the carb. A carb kit for this is about $14, complete with new adjusting screws. Adjusting screw intinial adjustment is 1-1/4 turns out from lightly seated.

Originally Posted by SkidMcSlide View Post
I have a Tecumseh 8 HP powered snowblower that is about 12 years old. I left stale fuel in it a few years ago and it has not run smoothly ever since.

I cleaned and replaced the carburetor but now just to get the engine to run I have to give it full choke and let it warm-up until it sputters then set the choke at . It will run for a few seconds and sputter again then I need to return to full choke. The only way to get the engine to run at all is to constantly switch between full and choke.

I have tried adjusting the fuel mixture screw at the bottom of the carburetor bowl but it does not seem to have any effect.

So far I have,
Removed and cleaned the carburetor.
Replaced the float and O-rings.
Drained the fuel tank and added fresh winter gas with stabilizer.
Replaced the spark plug and adjusted the gap.
Set the idle adjustment screw out one full turn.
Set the fuel mixture screw out anywhere from 1 to 6 full turns.

I am guessing that the fuel mixture is to lean but I cannot figure-out why the adjustment screw has no effect. Any insight into this problem would be greatly appreciated.
 
  #3  
Old 12-17-07, 02:07 PM
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Join Date: Jan 2007
Location: Central Indiana
Posts: 389
Ditto Indypower500.

You have passageways withing the carb that are still plugged. Take some stranded copper wire, peel back a few strands and use these to open up and clean out the small drilled metering holes. Copper wire is soft and won't damage the holes or alter their size.

Best thing to learn how to clean small engine carbs is to have a manual that shows the actual fuel flow within the carb; the route and orifices that fuel passes through on its way to the intake. Then you can follow this path cleaning every orifice and passageway. And don't forget that some of the brass components that you unscrew have drill orifices in them and are commonly overlooked when cleaning.
 
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