Sportsman 400, year 2001. Just put new rear tires on it, pulled the fronts and changed out the diff fluid.

My son took her out today in the backyard. She seems to do great in low speed mud type stuff. He took her put on the dirt road, and a mile in, she lost power. Push the throttle and she would jerk forward then sort of die off. Engine kept running fine. At one point he said it would not go forward, only reverse. When I got there, she was overheating and all the coolant was coming out of the recovery bottle.....

We had to push her up ramps into the back of the truck.

Any idea what is going on? I pulled the front tires yesterday and reset them. Mi did notice I have the left tires on the right and vice versa. Do you think that could have anything to do with it?

Appreciate any insight.

 

Jack the front end up with tires barely off the ground and fill with coolant. Check for any leaks especially around the water pump weep hole. Let the engine warm up with the radiator cap off to expel any trapped air.The fan should kick on and off several times,then top off the radiator and over flow bottle. Go from there and see what happens. Tires wouldn't have anything to do with it,but switch them around in the right direction.

 

Thanks OPT, I know your signature says you're retired and loving it, but me thinks you'd love to get your hands back in another Polaris! Or maybe not....

Just to follow up. When I got to where they were on the dirt road, she would go forward, but same thing, lots of power, then just bog...try again....lots of power, then bog. Gas looked a little low and we were on a hill, but not convinced that would have had anything to do with it.
I wonder if he didn't have it in low and AWD. Trying to go fast with that setup seems like it could be a recipe for trouble....
Also, I had to pull the brakes off to do the front wheels, I wonder if they aren't "on" and causing the engine to work extra hard. Like is there some sort of reset I am supposed to do when I put the brakes back on? (Totally unrelated but I want to drain and refill the front diff again, the fluid that came out was brown and jellyish, prob never been changed).

And I just want to add that I took her out last week, probably a twelve mile run. Mostly flat, some puddles. She didn't overheat, no loss of power, nothing abnormal.

 

Make sure the tank has enough fuel,pull the fuel line from the carb and crank the engine over. Should be a steady stream of fuel if the pump is ok.Try this in the on and reverse position.If the stream is weak,fuel pump could be weak. Plenty of cheap ones on ebay if needed. Again tires and brakes wouldn't cause this. Not a good idea to have the brake calipers off to begin with.

 

Ok, so started working on it. Fuel tank almost empty....never ask your teenager to check the fuel before a ride. Filled it with fuel, redid the radiator, that is behaving much better now.

Even in neutral, give it the throttle and she is strong for a few seconds, then dies off. If you continue to hold it or even increase it, she starts to sputter and almost stall out. Reverse weirdly seems very strong, although I can't really backup a hundred feet fast, lol!

Beginning to think it may be the fuel pump, but I can leave it idling forever, and it will not stall.

 

Problem could be trash in the carb if it was run low on fuel. One other way to tell if a fuel pump is weak(they can idle all day with a weak one) is to have an auxiliary bottle hooked up to the carb,have the line from the pump in a small pan and give it throttle. If flow is weak,then probably the pump.If it still cuts out,then could be trash in the main jet,float level off or can even be the limiter(in the speedo) faulting in forward range.Again make sure you check the on and reserve position on the fuel valve as to flow. Also not uncommon for a fuel valve to get stopped up over time.

 

Thanks! Managed to push her to the back yard where I have more room, and sure enough, she bogs down in reverse too. Lots of power first ten feet, then just bog and stutter.

I will pull the carb today and check it, might also change out the fuel filter. I don't know the last time it was swapped.

 

Are you pushing the over ride button in reverse? If not that could be the reason for it bogging in reverse also.

 

No, not pushing the override button, just straight reverse.
In neutral, she idles great, go to about 15 percent and she will hold there revving high, sounds like it's all going to be fine. Push it a bit more, and she bogs down and almost stalls. Same going forward and backward, stay about five miles per hour, and she will run all day. Try to go any faster and she bogs, stutters, and almost stalls.

Still pulling stuff off to see what is going on!

 

So dumb question: which fuel line should I pull from the carb? If I am sitting on the quad, I see two lines that come up into a T, then goes into the frame and (I think) goes down to the kill switch. From there, another line runs back to the carb. Is the fuel pump way up front by the radiator? I am just trying to figure out the easiest line to pull and see if I am getting strong fuel stream or not.

Thanks.