My 04 600 I have had since new.It has about 900 miles on it.Ibought it in the summer and it ran fine,first winter it had all the cold weather problems.
Had the cold weather update done on the carb it ran better but still would blacken plugs only at idle took it back to dealer many times over last 2 years but problem always the same I have tried bigger jets,adjusting mixture screw but nothing works.Once bike is warm its like ther was never any problems.If the bike has sat overnight and I pull the choke and start it it will start and run about 1 minute at about 1500 rpms then the rpms fall very quickly and the bike starts to sputter and stalls .It will restart but you have to hit the throttle and keep hitting it to keep it running until its warm but the next time I want to go out I have to pull the plugs or I have an even harder time keeping it running.At this point I am so frustrated I hate going out .
If anyone has any ideas Isure would appreciate it.......Sorry for the novel.

 

It sounds like the typical cold-blooded carb'ed Sportsman twin. My 03 600 "warms-up" the same way, it has the carb update and it's done right because I did it myself, some dealers just tweek the idle screw and call it good enough.

One thing I use in the winter during warm-up is a bandana or a Velcro strap lightly wrapped around the thumb throttle and handgrip to bring up the rev's a little so it does'nt sputter and die. I do this in neutral so the belt won't squeal if the rev's climb a bit. The engine will warm up faster and you won't have to nurse the throttle.

In below freezing temps I have an engine block heater that I plug in 10-15 mins before start up, it bolts into the freeze plug flange below the thermostat. Your Polaris dealer can get you one, the heater for the twins used to be listed on the Pure Polaris site but I don't see it anymore. I run NGK BKR7E spark plugs, they are better plugs and dealer recommended.

I also use a Uni-filter air filter, I figure a free'er flowing air filter like a Uni or K&N would lean the fuel mixture out a little bit and help with plug fouling. It sound like alot but it's just a 10 minute warm up, then your good for the day. I have a blast riding my 600 in the snow and use it more during the cold seasons than in the summer.

 

sounds like it is to rich, try lowering the needle in the carb one notch. You have to take the carb out, take the four screws out of the top, lift out the rubber diaphram and the needle will come with it, turn the slide upside down and the needle will come out. there should be a plastic washer on top of the needle , dont lose it. Raise the little clip one notch on the needle this will lower the needle and lean out the carb .Try it , its not to hard .

 

Thanks for the info Iwill try moving the clip and see if that helps ,Andre does the block heater make a big diffrence where I am its allways cold.

 

The heater was installed by my dealer who saw no need to do the carb update, so I updated the carb myself. Since I have the block heater I use it on days below freezing , it just speeds up the warm up process, depending how long it's plugged in.

The "E" clip on your jet needle sould be in the third position down from the top according to the Polaris TSB for a 600 twin. My NGK's do not foul, but the engine still needs to be fully warmed up to run right. I suppose I could mess with the pilot screw some more but it only idles like crap in freezing temps.

 

I have a 2004.5 Sportsman 600 that fouls the plugs in the winter also. what is a winter kit and what is involved in the istallation of it. thanks

 

Could it be that the choke is not releasing all the way when you push the **** in. On the carb end of the choke cable is a small brass piston, if that piston is not returning all the way, the motor will run rich. You would not notice it as much if you have the throttle opened up cause you are lifting the slide and leaning out the mixture. When it is at idle the slide is almost all the way closed creating vacum. The choke is not really a choke, it is an enrichment jet, once the motor is warmed up the piston on the end of the choke cable is supposed to close the enrichment jet, if it dosent it will blacken and foul plugs faster than a cat can lick its a$$. You dont need to pull the carb to check it, just follow the cable to the carb and there is a threaded plastic collar that the cable runs thru. Be careful the collar is plastic, but unscrew the collar and pull it out of the carb. Now you can check that the cable moves freely in the housing. Clean all parts up good , put a little grease on the piston and reinstall, dont overtighten the plastic collar. This happened to me and this worked. One other thing to check is there is a vent tube that comes off the carb and goes up. this vent is to equalize the pressure in the carb, if it is pluged the motor will run bad.