Recently got a 95 XPlorer 400 Demand-Drive AWD. Figured out all the other mtce items that comes with this model, but I have a nasty issue with the ATV not wanting to idle and having a real bad time of oil-fowling the plug repeatedly. If I sit too long at idle on the trail it will finally idle down too low and die. Does not matter if its cold after startup or after it is warmed up from driving. The idle adjust screw per the manual should be 1-1.5 turns out, but that just causes the ATV to die right out because the idle is way too low then. The idle screw is almost all the way in (about 1/8 turn out) to even get it to atempt to idle. It was also running real heavy on the oil as the smoke was pretty bad coming out the exhaust.

I did find a rather large break in the carb to airbox boot and took care of that so no more junk getting sucked into carb. It seems to have more than decent power when I open up the throttle but it continues to not want to idle and oil fowl the plug. I took it to one of my local Polaris dealers and they supposedly did an adjustment to the carb idle and mixture settings (charged me over $100.00 bucks for the work). But it still will not idle and continues to produce more smoke than I think it should be.

I have cleaned the carb but is it possible the carb has crud in it from the airbox leak? Or is the carb or related oil inject portion just worn out? As you can tell, I have dug right into this thing to get it ready for the trails but this engine idle and plug fowling problem is driving me nuts!!!

Any suggestions on which direction to go look at would be appreciated. I for sure will not be taking it back to the Polaris dealer that I previously took it to. I try to do most all the work myself if at all possible. Thanks in advance for any assistance you all can provide.

Thanks ...

 

If you found a tear in the air box boot there is a good chance your top end is worn out.

That can cause some of the problems you are having.

For now back out the air screw and turn in the idle screw.

 

do a compression test to verify the post above, he's correct.
If that tests out good then take a look at your pilot jet size and needle position.

 

I also have a 95 xplorer. When I got it, it wouldn't idle correctly so I took it to the local dealer and they determined the following items needed to be addressed. The most expensive was that the compression was down below 80. This required a top-end rebuild including an overbore and new wiseco piston. Also the reeds were replaced. The other issue was that there were some vent tubes that were blocked causing the carb to malfunction intermittently. After I had the re-build done and installed new vent tubes, the thing now idles great. Now it idles a little slower when cold than when it warms up. I set the idle to be slightly higher than recommended when warm.

 

Guys, thanks for the great info to check on. I had not even thought about blockage in the multitude of vent tubes on this thing. I had thought about pulling the carb and valve boot to check the reed valve but I figured since it was running pretty well above idle that the reed valve should be fine. Is that a misunderstanding on my part??? Also, I have the oiler adjustment set to spec but how do you really tell if the oiler is delivering the correct (or incorrect) amount of oil into the carb? Since it seems to smoke fairly heavy I feel it has too much oil going intot he carb for the mix. This may also be contributing to my plug oil fowling quite frequently.

I have already checked / changed out the counter-balance oil, transmission oil, Demand-Drive hub oil (ATF type-F), greased every fitting I could find, replaced the carb to airbox boot, replaced air filter, adjusted the center and front chain tension to specs, but I sort of missed on the rear chain. Blew it out this past weekend on the trail and it ate the chain guide too. Plus found my left front CV boot with a hole in it so I am going to replace both sides while I have it apart. But what the heck, its a '95 model with a few miles on it so some mtce is to be expected!

Thanks agian for the great advice. I plan on being back in it again tomorrow night after work thru this carb issue.

 

My xplorer does not smoke heavily - you can barely see a wisp of white smoke from the exhaust on each exhaust stroke but it dissipates quickly. I've never had a fouled plug either. When the dealer repaired the top-end they said they left the mixture a bit rich for the break-in period. I've got about 10 hours on the engine now so I need to probably lean-out the mix a bit. By the way, what type of oil are you using? I've been using the standard Polaris brand but I"ve heard the synthetic variety doesn't smoke/smell as bad so I may try it.

 

I've been using the synthetic oil on my Explorer 400 for about a year or so. I think it does help on the smoking and smell some, although it's hard to tell for sure because some of the regular oil would still be in there. I don't know about the rest of you, but I wouldn't trade my 2 stroke for a comparable 4 stroke any day! I've raced it against a 500 HO and also a 700 twin, and with both it was neck and neck!