2018 Polaris Sportsman 570 wont start

[Magnificus]

Hi everybody. New in the forum and from Sweden.
The machine ( Sportsman 570 2018) has been in duty on a farm for three years, last week, worked like normal for an hour or so, was left at idle and suddenly died spontaneously. Did not start at idle as it uses to do. Gave a little throttle, then it started, and sounded ok, no rattling as far as I could hear, but no power at all when I gave it throttle and died when I released the throttle. Now when it has cooled down, it does not start at all, but it tries to start every now and then. When we run it at the start, it pulses air OUT the intake. One theory is that the cam chain has been slack and cogged over and the intake valves are a bit open during the compression phase. It could explain that air is blowing out of the intake in that case. Is this possible without valves breaking or the camshaft collapsing. And the recipe? Set the cam, change chain and tensioner? Or am I completely out in the blue, more ideas? 
regards Magnus

 

[pikachu78]

my guess is to try cleaning the carburetor jets and try doing a valve adjustment

 

2017-2022 Sportsman 570 6x6 Service Manual.pdf

[MarkinAR]

Puffing air out of the intake is 99% of the time due to timing being off (assuming it's not just lean and backfiring through the intake) and that may indeed be timing chain jumped a couple of teeth.  Given that it's fuel injected, I doubt it has a clog, but you could pull the injectors/throttle body anyway and check just to make sure because it's an easy repair.  Pulling the head and checking the valve condition is also fairly easy to make sure it hasn't burned an intake valve.  It's possible and would be that other 1% of the time where it puffs air out the intake.

Looks like it's just going to be a series of diagnostics and working through it.  @pikachu78 was kind enough to link the repair manual above.  Just grab that and start prodding around, you'll find it sooner or later.

[Magnificus]

Hi, and thanks for your engagement. Yes, the repair manual seems to be over all covering and, safety first, I will check te valves and chain before doing anything else.

[spock58]

I'd be curious to know what the compression is - did you test it yet? If it's only three years old, does it have lots of hours on it?

Your issue may be electrical which also affects fuel system with efi.

[Magnificus]

No, haven’t tested compression yet.