Surges at idle

kettle

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#1
Yard machine by M T D. B&S 17 hp twin II. Engine surges at idle and will stop running if I hold the throttle to idle screw. What is the cause of this and how do I test and repair it? Thanks Kettle
 
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#2
you have a low mix problem.check to see if the carb has a low mixtue screw on the side.it may have a limiter cap on it.it is located below the idle speed screw.you may need to open it up a little.i sometimes remove the screw and shoot carb cleaner through it.then replace the screw ,bottom out and turn out 1 1/2 turns.you can also drop the fuel bowl and check for dirt..give it a try.
 

kettle

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#3
Carb has no low mix. screw. Fuel bowl looks clean. Cleaned with carb. cleaner anyway. I can stop surging by closing choke part way, so this means I have air-fuel mixture problem at idle. There are 3 sall holes in top of carb. I can spray cleaner into these with a straw and the engine will idle ok for a while., but it will surge again 10 to 30 min. later. Is my only choice a carb. kit or is there something else I can try? I have sprayed start fluid all around carb and intake, but no air leak was indicated. Kettle
 
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#4
other than soaking the carb in cleaner overnight and rebuilding it.you may have to go with a carb.probably a blockage internally in the carb.try blowing compressed air through all the ports?if you get a kit it will have the plugs in the kit.removing them from the carb will reveal tiny ports that get glogged.not sure if that carb has them without a picture of it.
 

kettle

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#5
Thanks, I will remove carb. clean and install kit. Will let you know the results.
Kettle
 

kettle

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#6
I removed the carb, cleaned it with carb cleaner. It works fine now. Thanks for the help.
Kettle fixed