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2001 Polaris sportsman 500 HO engine fan and bogs at high throttle

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Old Oct 2, 2017 | 06:13 PM
  #1  
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Default 2001 Polaris sportsman 500 HO engine fan and bogs at high throttle

Hey OPT,

My wheeler is running pretty good at idle and medium throttle, but has been bogging down when I give it full throttle. Is this a needle valve clip setting prob or fuel screw adjustment or what?

Also, the engine fan seems to be coming on fairly frequently, even at idle and in 30 degree outside temps. Is there a cooling system troubleshoot process you recommend?

Thanks!
 
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Old Oct 2, 2017 | 07:33 PM
  #2  
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This can be a stopped up main jet,trash in the carb,ect.If you take an older carb out always rebuild it,don't just try to clean one up and expect to always solve any problem.You shouldn't have to take a carb out more than once.Polaris Sportsman 500 Carburetor Repair Kit Fits 2001-2002 Carb: Shindy 03-408 As far as the fan coming on frequently,trapped air is usually the major problem on this,sometimes a thermostat can be sticking also.Pull the thermostat and see if it open fully in boiling water. If it sticks,replace it.Raise the front end,tires off the ground,leave the radiator cap off and see if any air can bubble out at the top of the radiator.Add coolant as the level goes down. See if the fan settle down and cycles on and off. Hard system to bleed as the coolant return line(#7) goes back to the filler neck and not straight to the radiator. This was finally solved on the 2005 models.
 
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