Went muddin today on my 2000 Trailboss and on the way home at full throttle it acted as if it was out of gas just wanted to die on me checked the gas level still had 1/4 tank i put it on reserve any way and nursed it home at half speed. Now no bashers please because this is the first problem like this since i have had the machine a little over a year. Could i have fouled the plug it is the original or could it be something else more major? The only mod i have is a K&N filter and i was pulling out my buddy quite a bit. some of the mud was tire deep. please help supposed to ride again tomarrow. oh i also spun the chain off no big deal except being knee deep in mud and having to be pushed out

 

Did switching to reserve make a differance? If so, you may just have a clogged valve. 4 strokes don't usually have the spark plug fouling problem that 2 strokes have. But it's not unheard of. You might want to try a new plug, but I'd also check your oil for water (milky appearance). And while you have the plug out hold your hand over the hole and hit the starter. See if you get any moisture on your hand. Curious to see what you find with this one. Good luck.

 

also when i got home it started right up and backfired but seemed to idle fine after i washed it

 

I had a similar problem with my Magnum 500. I was breaking a trail in some deep snow at full throttle. When I stopped, the engine quit. It would not restart for quite a while. As far as I can tell, I flooded the engine. I was running full throttle, but the engine RPMs were not very high and when I stopped, the unburnt fuel flooded the engine and it quit. This is the theory me and my buddy came up with. We towed it home and when we got there it started right up. I havent rode it yet to see if it runs ok still, but I think it will. Had a friend of mine with a Wolverine with valvetrain problems and it acted very similar. The oil pump in his motor broke and the valvetrain was starved for oil and siezed the cam. Does anyone know how to check the oil pump to see if it is working? And does Polaris use plastic gears in the oil pump like Yamaha?

 

I checked the oil it looked fine but I changed it anyway since it was due as for a clogged valve how do i check this i really didn't get on the throttle to much after i put it on reserve

 

Make sure the vents to the gas tank and carb didn't get plugged with mud or kinked. This can make it act like it is running out of gas when it isn't.

 

I had a similar problem, Let me ask you this. Is your air filter a paper filter, and if so did it get wet? Have you run your machine recently after letting it sit for a day or so?? If not, take out your filter and let it air dry for a day or so. My problem was a wet filter. It was unable to suck enough air to run properly because it was saturated with water. Made it run exactly like you describe. Hopefully this is all that is wrong with your machine. I have a SP 500 99