Well, today while we were riding, our '00 400 Xplorer with 120 miles on it started acting like it was flooded about 5 miles into the ride. We stopped to see what was going on and the engine totally quit. We tried to crank it up, and finally got it cranked with about 1/4 throttle in. It still acted like it was flooded and would not idle. We popped off the ETC throttle cover- everything looked right-points had about 1/8 clearance. Then, we tried the plug. The plug was all black and looked flooded. We put another one in- Still acts the same. Now I don't know what to do. I was hoping that some of you could give me some advice. Thanks for everything, Nick

 

Well sorry I can't help you with your problem because my 400 exp does the same thing and now won't even crank I will let you know what I find but keep me informed because I am lost too

 

Stuck float in the carb? I had a CR 125 that did that and I had a float that was sticking. If you take off the carb, remove the main jet and blow air through it to make sure it is clean. If it is under warrantee, make Polaris fix it. We ride with an older 400 and it has been trouble free.

 

I agree with Weedy, the float in the carb may be stuck. Before you take the carb apart, though, there are a few simpler things to check. If you drove your 400 for very long in a barely-running state, you may have enough gunk in the engine to foul up the new plug. If you have another plug try it, but first, take out the old one & leave it out for a little while. Crank over the engine a few times to try to get some 'dry' air into it. It also wouldn't hurt to take out the crankcase drain, if any amount of fuel at all comes out the carb float has to be stuck. A couple drops could just be flooding. Anyway, now leave the plug out overnight if you can & put in a new one in the morning & it should start. If it does, do NOT shut it off until you get it good & warmed up to burn out any gunk. As to what plug to use I have the 3 best choices listed here.

1. NGK
2. NGK
3. NGK

Also, once a plug fouls, you will likely not ever get it to work well again.

Once I replaced the plug on my Xplorer 400 & it ran like CRAP and soon died & wouldn't start. I felt like a fool later, though. The spark plug wire wasn't on tight enough! It takes a lot of force to lock it on, and it is hard to reach and harder to see if you got it straight. I resorted to trying to tug it off to be sure it locked onto the plug end. Good luck, guys.
Farmr

 

I had a 94 400 and it fouled a lot. Turned out that it just wouldn't run good with the stock paper filter. I went to an after market 2 stage foam filter (K&N) and never had another problem. Funny thing is, my friend rode the same year model 400 and never had this problem. This may or may not be the case with your bike, but a K&N can't hurt. Hope this helps. Good luck.
www.atvnalaska.com

 

Couple of questions: When does it do this, i.e., while running wide open, half throttle, or after idling for a long time? If while running at full throttle, the main jet is too rich and you need to go down 1 jet size. Something else to check is the oil pump adjustment. It is set too rich from the factory to ensure adequate lubrication during break-in, but needs to be reset after break-in. The procedure is outlined in the owner's manual. My 2001 Xplorer 400 has run great. Hasn't fouled a plug yet, and can idle as long as I want it to without loading up. I did adjust the oil pump, so if you have any questions regarding adjusting it, just ask and I will try to help. I run 93 octane pump gas, but I don't know that it's any better than 87. I just like spending the extra $$. Occasionally, mine does load up when in a mudhole under full throttle. The main jet needs to be changed out to a smaller one. If it keeps it up, I'll go ahead and get another jet. Hope this has helped you.