Today I took my Sportsman 570 for a long ride, and at about 20 miles it started to loose power and then backfire. I turned the ignition off and waited about 2 minutes and then restarted it. It ran great for about 2 miles more and then started to loose power and backfire again. I had this happen about 4 more times until I got back to my trailer. Does anyone have any idea about what's going on?

 

Sounds like something a weak fuel pump would do,but is it throwing any codes? If not then it's best to have Digital Wrench find the problem.The service manual can help,but only so much you can do with a meter in the garage. I'd at least check the connectors and wiring from the tps and tbap sensors for any bare or soft feeling wires that may have melted internally. Also wiring from the crank position sensor that may be intermittently grounding out to the engine.Not sure on the 570,but the other atvs had 39psi +/- 2 psi that the fuel pump had to hold steady.

 

Thanks for your help-- I'll see what I can find.

 

Update--I had the fuel pump checked and it had 60lbs pressure. I took it out for another ride and the same problem again. I decided to change the fuel pump and then another ride 28 miles long and an elevation climb of 5000 ft--NO PROBLEMS, it ran like new!!

 

Sometimes hard to trace intermittent problems like this but sounds like the fuel pump even though showing good pressure could have been shorting out,loosing pressure when it got hot. Glad a new pump solved the problem.