Runs only with choke on!

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  #1  
Old 02-09-03, 07:49 PM
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Unhappy Runs only with choke on!

Hi all!
Have a problem with my Briggs & S. (401400) older 16.5 HP. It's the heart of my White Lawn Tractor.
Hasn't been used in a couple of yrs. Stripped down the carb. and soaked it in carb. cleaner for 30 minutes, blew it out real well and reassembled. (normally this seems to fix whatever ails it). Fired right up but will only run with the choke on full. Any attempt to slightly open the choke and it dies. Both the high speed needle valve & idle needle valve have been opened 1 1/2 turns. It also seems to be missing/sputtering with an occasional small backfire through the carb. but all this is very slight. With it only running in full choke, the high end rpm is not what it should be and turning in the high speed needle valve one complete turn makes it run a little better but not enough. It also appears that the high speed needle may be worn as the point is rounded when you compare it to the idle needle which is pointed.
Thanks for any help offered.
 
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Old 02-09-03, 10:55 PM
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Hello msabot!

I'm assuming this is a horizontal shaft engine since you mentioned a high speed adjustment screw. It sounds like your carb still has a restriction in it. It could also be a mis-adjusted float. If there is still a blockage after a good cleaning, there's a good chance that the nozzle is restricted. It is a long brass thin tube that extends through the throat of the carb and meters out fuel. If this is a vertical shaft engine, you wont have this.

Let us know what you find!
 
  #3  
Old 02-10-03, 07:35 PM
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Thumbs up

Thanks for your response Cheese!
Tore the carb. apart---again. Let it soak in cleaner about an hour, checked the float level and reassembled. It ran much better, as it was able to run with the choke open about 3/4's of the way. Still miss firing and not quite at top rpm, I think I'll try to soak it in carb. cleaner overnight.
Thanks again.
 
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Old 02-10-03, 10:06 PM
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Anytime! Let us know how it turns out. If you have access to an air compressor, use a rubber-tipped blower nozzle to blow out all passages after you get it out of the cleaning solution. Make sure to wear eye protection when doing this.
 
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