Hi,

I have a 2001 polaris Sportsman 500 HO.
It will start up just fine after it has sat idle for a hour or so, put once it is started up for about 45 seconds to 1 minute it will cut out really bad and then sometimes die. It does not matter if your sitting idle in neutral or moving. Or throttle postion.

I have plenty of good gas, clean air filter and a new fuel filter. I thought maybe it was the reverse limit switch, but it still acts up when pressed or not and in all gears.

It is running like the choke is stuck in the on position or it is not getting enough fuel.

I'm a little stumped as to what it is due to the fact it runs perfect for about 1 minute and then acts up.

Any help would be great,

John

 

Im glad u posted this...I have an '06 scrambler which I bought brand new and it does the same thing. It seems to only happen after a thorough power washing...Has never happened while riding on the trails,mud,water ect.... I try not to blast the electronics or anywhere that looks tender. It is very frustrating because it should be able to take on a little water. I contacted dealer and they said to try putting Dy-electric(not sure how to spell it , because no one around me has heard of it) grease on the conections. I used some regular grease and it seemed to help, until today I was done washing/drying it and drove around for about 1 minute and it did it again. Doesnt stall, just acts like I was in reverse and tried moving not holding in over- ride button. Im lost, frustrated, and could use some help also..

 

I'll see if I can give you some ideas on where to start and clarify a few things so we can get you looking in the right areas without causing further problems. First Motohoppie, I would get a new spark plug in there just to eliminate the possibility of a partially fouled or cracked spark plug. It really does sound like a fuel delivery problem though. Did the problem start all at once or gradually worsen with time? If it is running like the choke is stuck on, you should be getting some black smoke from the exhaust.(rich) You should notice a stronger smell of fuel while it is running, and to restart it after it dies you should be having to open the throttle and spinning it over for quite some time to get it to restart. Again at this point you'll probably noticed excessive black smoke, which is the excessive fuel which is not being completly burned. If on the other hand it's not getting enough fuel you won't see any black smoke from the exhuast and it will probably stall worse the quicker or farther that you open the throttle. It also should stall worse in gear or under load if you you aren't getting enough fuel.(lean) You do state that it runs perfect for about 1 minute which would point me to the following things to check. I'm not sure where it's located but there will be a vent into the fuel tank. It could be in the fuel cap or a tube that comes off the top of the fuel tank up under the plastic. If this vent or tube that's hooked to it as the case may be, is stopped up it will prevent fuel from flowing down to the carburetor and could cause the condition you described. As fuel flows out of the fuel tank, air must flow into the tank to replace it or a vacuum will occur and stop the flow of fuel. (Like capping your finger over the upper end of a straw in a drink and being able to lift the drink up in the straw without it flowing out) Same thing happens to the fuel in your tank; it can't flow until air can get in to replace the area where the fuel was. Being that fuel does weigh more than air it takes a little while for the vacuum to build up enough inside the tank to overcome the weight of the fuel and stop its flow enough to cause the engine to stall. You also talk about it starting up fine after sitting for an hour or so. This also makes me think it's a tank vent problem. After an hour or so of time enough air can probably seep back into the fuel tank to allow fuel to once again flow enough to refill your carb bowl and allow it to "run perfect"for another minite or so before the problem repeats itself. the quickest way to check to see if this is the problem is to start it with the fuel cap loosened up or off( be careful not to splash out fuel if you completely remove the cap).This will allow air into the tank as needed so fuel can continue to flow. You will know that this is where your problem is if it continues to run without problems. This is not a repair as you don't want to ride with the cap loose or off by any means. Find out where the tank vent is.(If in the cap ,replace the fuel cap) If it is a tube off the tank then find it and either get it unstopped or replace it. People who ride in deep mud tend to get these clogged up with dried mud if they haven't rerouted them up out of harms way. Insects,(bees,spiders etc) also sometimes get in these rubber or plastic tubes and stop them up. I won't go any further with your problem than this for the time being Moto, as I feel that this more than likely may be your problem. If this doesn't do it we'll dig further. There are others here who may give you some other ideas to try also. If you don't get a response, just keep trying or "bump " your post back up to the first of the list occasionally and some of us will try to help you. Hope this wasn't too long or confusing. Remember, loosen /remove the fuel cap and see what happens. Good luck. Welcome aboard the forum.

OK superdeuche, Not sure I can be as helpful on your problem, but we'll do what we can. The spelling is "dielectric" grease and it is usually available at most any auto parts or hardware stores. Dielectric grease will not conduct electricity as "regular" grease will. You need to clean the regular grease off the connections ASAP as this really could cause you further problems such as short circuits and possibly electrical system failures or fires. The dielectic grease is also very waterproof compared to regular grease and prevents water and contamanents from getting into your connections and causing problems. Get some electrical contact cleaner in a spray aeresol can, disconnect and clean those connections completely. Then repack the connectors with the dielectric grease and make sure they are connected back properly. It does sound as if you're getting water into something that it shouldn't be getting into. The only other things that come to mind on your problem could be possibly a split or cracked coil to spark plug wire[img]i/expressions/face-icon-small-sad.gif[/img]would probably show up in mud or water riding though) Or possibly that you are forcing some water into the vent tubes that go to the carburetor and the water isn't enough but to cause it to miss and not completely stall. (not very likely but possible). One other thing; Is there any way you could be getting water on the air filter during washing? This should be easy enough to take a look at after washing just to see if there is any water getting into the engine here. If water is getting on the filter it could be getting pulled in through the filter or it also will clog the filter pores and cause it to run rich(like the choke is on) until it dries out and then it probably will run fine again. Hope this helps. Again, welcome aboard and keep us posted.

 

Thanks for the help... I will get the dielectric grease and do what u said.

 

I fixed the problem.

There is a foam piece that sits under the front of the seat that hugs the snorkles. It was slid up under the fuel tank cutting off the air intake. I have not yet took it out and fully tested it, but soon will.

I purchased the ATV used and I'm not sure where this foam piece fits exactly. Anybody know?

Thanks for the help,
John

 

There is a pre- cleaner filter that goes over the air intake snorkel, the foam piece goes over that to hold the filter away from the tank. Check your throttle cable adjustment, it is about 4 inches away from the throttle, there should be very little slack in the throttle, to much will make it cut out like the overide does.

 

Sorry,Moto, I see I guessed the wrong way on your problem. You actually were experiencing a rich condition instead of lean as I first thought. Glad you found it and it was something simple to fix.

 

I have a 2001 HO that was doing the EXACT same thing. I rebuilt the fuel pump and it fix it.