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Discussion Starter #1 (Edited)
Warning - This is long, but I would really appreciate the help!!

Hey guys, new to the Polaris atvs. My dad just bought a 03 magnum 330. Nice machine. Got it home and started doing some general maintenance that I like to do as soon as we get something new to us. Pulled the carb and cleaned it, cleaned and oiled the air filter, adjusted the valves (nothing new to me).

This machine always had a bit of a lag to it when started, cold starting it took forever to warm up. Bad hesitation from idle to half throttle.

Was careful about cleaning the carb. Replaced the plug, still wouldnt run correctly.

EDIT: After a short run time with clean carb and new plug - new plug was turning white and the head pipe would glow red hot, also some light backfiring through the carb on warmup. Pointed me toward the machine running lean*

After talking with a tech at the local dealer - he told me that these carbs are very common for this and that it needed to completely come apart to be cleaned - remove jets and all - no big deal.

Now - where my problem starts is the idle / air mixture screw, someone had already removed the plug that covers it, and had stripped the head badly. i carefully carved a groove in the screw with a pick and got it turned it to the seated position to turn it back out. stripped it completely, cannot get it out. have tried everything - including breaking off an easy out in it. Now im screwed.

Need a new carb. It is a Mikuni BST31 model according to the service manual. Ebay shows the carb working from 2003-2006, but by the manual 2003 is the only one using the bst31 carb. The rest are BST34 with different jetting. A new carb is $450+ and basically out of the question.

Can anyone tell me if this information is correct? If there is another machine i can get a carb from that is compatible? Or any other suggestions???
 

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I found these carbs on ebay new for 125 bucks.its been a week since i ordered mine and i havent gotten ityet. When i get it and make sure its the right one ill let you know.........i checked and he doesnt list the 31's,just the 34's...... Sorry
 
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