I have a 1997 Polaris 400cc Sport. I can drive it for 5 hours some days and it runs great no problems, the next day I could ride it 5 minutes and it dies. It acts like it is not getting enough fuel or it is getting too much fuel. I cannot keep it running when it is going through one of its spells. Then I will let it sit about 3 - 5 min and it will start right up. Now here is the wierd part then my four wheeler will either run fine for the rest of the time, or it will ride for about another 5 - 10 min and do it again. Then the next day it may run 2 - 3 hours or all day with no problems then all of a sudden out of the blue it starts bogging down and then no matter what I do I cannot keep it running. Sometimes if I turn the choke on during the dying phase it will snap out of it and run good for about another 10 min. Weather does not seem to affect it. Days it is hot it may do it or it may not, on cold days it may do it or it might not, but it is getting real frustrating because I have been trying to troubleshoot what may be wrong with it but like I said some days it runs all day without any problems and may go for 3 or 4 days straight and I will think it is fixed and then out of the blue it happens again. I AM SO FRUSTRATED can anyone HELP ME!!!!!!!!!
Oh yeah one other thing My Four Wheeler Runs Great when this is not happening no missing, no hesitating, nothing at all.
Thanks,
J-Dogg

 

check the line vent thing on the fuel cap it could be clogged causeing this... or get some fuel conditining

 

To check the vent hose when it starts doing this loosen the gas cap.If you have had the tank off it is easy to pinch the vent line.