2001 quadmaster 500 runs rough after half throttle

[paul d]

hello , new member here , i bought a 500 quadmaster that had sat in a shed for 4 years the guy said he just parked it when it quit running at just over 2000 miles , he said he an his dad tried cleaning the carb an they messed it up an quit on it , i cleaned the gas tank an put new petcock on it , bought a carb kit an cleaned the carb ( made it look like a new one ) the tank also , well i put in the new kit adjusted the air jet 2 1/4 turns out , new choke cable , new battery , new spark plug , when i got it back together it started right up did'nt even have to use the choke , i got on it an went down the road after half throttle it runs super ruff , i took it all apart again thinking i did something wrong , followed a diagram putting it back together again only to get the same results , an when its cold you dont ever have to use the choke it always starts right up , any ideas on what to look for would be greatly appriciated , i live in the mountains an any repair shop is over an hour away an the cost per hour is riddiculous , thank you for taking time to read , almost at wits end

[davefrombc]

Try  adjusting the air screw first .. The 2 1/4  setting is  just the initial setting   and  could  need some  fine tuning ..  You want it  where  it starts and idles ok  and doesn't  bog when  you  open the throttle. It's abit   of  fiddling  between  too  rich and too lean .   You  may  also  need to  adjust the  height  of the  main  fuel  jet rod so  it  gets  the right mixture  at  your  altitude. try  moving the  clip  up (  needle deeper  in  jet) if it seems to be bogging  on too  rich  for your  altitude ..  Moving the  clip  down  will   richen the  mixture  on  the  main  if it  is too  lean .

[paul d]

thank you for the reply , i'll try that , i'm going to take it apart one more time , a friend stopped by while i was working with it an he said it sounded like it was running to rich , this is my first atv an not sure how to adjust it , the only adjusting on the houseing is the air an idle , thanks again

[davefrombc]

There  is a clip that sets the depth the tapered main  jet needle goes into  the  jet. If the  needle is set too high (clip  in  a  lower groove) it will  run   too  rich.  If  it is  in fact  rich too  rich  ,try  moving the  clip  up  ne  notch  and try again . You  may need to  do  it  a couple of times to find the sweet spot.

[paul d]

thanks so much for the input , a couple times moveing that clip an some adjustment on the air jet ,got it running like a new one , well worth the $700 total i got in it , again thank you