I had the same problem with a 400. The solution, smaller jets. When it got hot it was getting more fuel then it could burn. If you can duplicate the problem stop the engine and pull the plug. My guess is it is going to be wet. If so, something has gone bad in the carb. I don't know about you but after narrowing down problems like this it sometimes helped to disassemble and reassemble.

Let us know what you find.

 

peakgolf: did you ever figure out what the problem was? I've got an 04.5 sp 500 that has similar symptoms. I'm with you and think that it's a weak fuel pump as everything else I've tried in the carb, smaller jetting, had no affect.

 

I have two 400 sportsman 2005. They are doing exactly the same thing you are describing. They have been back to the dealer three times. What size jet did you put in your bike. I am becoming very frustrated and embarrassed as my neighbors King Quads walk all over the hills I cannot seem to go up.

 

Does it ever flash HOT HOT on the Lcd? My wifes SP450 would cut out when the
RAD was plugged and I think some reported stalls related to the
ECM-recall problem (May explain a few more of mine). -- All fixed now

But recent replys about the CARB is the real winner in those. That happened with
me too. Do a good carb clean and drain the gas anyways, add fresh, look at the
throttle cable mine was off a little and now its idle is right on the mark, several things
added to my cut outs. And if you do all these and still have problems, change out
that Spark Plug pretty cheap. I fouled mine from all the CHOKE starts I am sure.

Cheers,

R'

 

hey I see this is a older post was wondering if anyone found out a problem .I have just recently purchased 2006 sportsman 450 browning addition .and was at hatfield mcoys .problems seem worse when its warmed up . has less than a thousand miles on it but previous owner drove around its whole life on 11 acres .it has new air filter new plug and new belt when you cruising around it starts spitting and sputtering like its starving for fuel.yet it seems to burn a lot of fuel like 10 miles to gallon .local atv shop in man wv tried helping couldn't figure it out they sucked out tank sea foamed it and put fresh gas .I only run 93 octane. and he ran it down the highway and he thought it was fixed .then I put it on incline in his yard and he saw what it does .they thought cause it was rolled over once that it was a rollover switch but I don't think it has one I m not sure ? he pulled bowl on carb and he said it was clean as a whistle.iv seen some post about rejetting .ect just don't want to go on a part buying expedition I was leaning on fuel pump .but its definitely a incline issue .someone said it could be clutches .can see how that would be it I would think it would happen all the time .it is worse in high range than low range .but its prevalent in both . saw some one say something about tire size thew browning edition came with 26" tires .it definitely seems like a engine performance issue could this be ecm issue?ive seen stuff about recalls anyone know anything about that?or have some wisdom or experience with this problem

 

Bowl might be clean but what about fuel tank outlet. They typically have a screen filter inside the tank, could be gummed up. Seafoam is good but slow if really gunked up. Do you have a good hot blue spark to the plug capable of jumping an eighth to three sixteenth gap? Try disconnecting fuel line from carb and see if you have good fuel flow. I would drop carb bowl and spray carb cleaner up in there to be sure float and jets are not gummed up. If all else fails might be time for a good carb rebuild with proper kit. Sounds like fuel delivery problem from your description.

 

Seems like some junk in your jet. Like said above. Good carb cleaning. When you think you did it good enough, do it again.
Another thing to look for, is holes in the intake boot. Take it off, and give it a good look. Mine did the same, and found the boot had a hole around the bottom, where it clamps up to the carb.
I wouldn't say it's ecm related. You can run your VIN through a dealer, and it will tell you if it has been replaced under warranty or not.

 

I carb off now getting rebuild now we will see let y'all know

 

Try spraying some fuel around intake, if engine changes speed you have an intake leak. Have a fire extinguisher on standby as you are playing with fuel on a hot engine. No matter how clean the carb looks, a sticking float or needle valve can still stick.

 

My 500 doing same...what did you learn?