Had an 500 traxter with ruff idle...I cleaned carb and replaced gaskets and float value,adjusted fuel level several times still rich idle....after hours of working on this..I turned the fuel value off an bout 3 seconds great idle ..I did notice when rich and ruff idle the carb never was showing any signs of extra fuel.. so after I turn fuel value off for bout 3 second great idle I started thinking how could this be..i NOTICED The fuel pump was vaccumed pulsed so I put an clear line on the vuccum pulsed nipple an bingo seen fuel getting pumped into intake to cause the rich and ruff Idle..Replaced fuel pump an runs great Im just sharing this to save some others some time on an rich and ruff idle after you have gone thru the carb time n time again...may want to do to this test on pulse to pump to see if pump okay.

 

Great post! Found the same thing on some Polaris fuel pumps. If pump diaphragms are leaking it can suck raw fuel into vacuum side of the carb causing a lot of people to pull their hair out in frustration trying to find out what's wrong. One quick way to usually tell is to pull the vacuum pulse line and if it's the least bit moist,time to replace the pump.

 

Thanks OPT..Yes I had moisture in pulse line so put an clear line on nipple to start so I could see if pump was putting fuel in intake...Yes your correct some other atv with this type petcock or fuel pump has problems... Thank you for ALL you do here for us all.