I have a 2008 Sportsman 500 HO. Starts breaking up (skipping real bad) once the engine comes up to temperature. I replaced fuel filter, fuel pump, spark plug and then the carburator. All to no avail! I'm thinking now it's an electrical problem.Would my coil or ECM be laying down once they warm up? When the engine is cold it won't start breaking up until it's at WOT. Once the engine is at temp it breaks up badly even under slight acceleration I've read that there was a recall for the ECMs. How can I tell if it has been replaced? Any help would be greatly appreciated!!

 

A 2008 is to new to be on the recall. ATV : Polaris Ind. expands recall of ATVs looks like its just 2004 to 2006.

 

Ok. Thanx for the info!!

 

Pull the 16 pin speedometer connector and run it this way until it's warm.If it runs without missing then it's possible the built in speedometer reverse limiter is shorting out. First test that it shows on my pdf manual for the 2008 model to do. OPT

 

OPT,
I unplugged the 16 pin connector but could not start the engine. I then plugged it back in, started the engine and then unplugged the connector and the engine stayed running. Went for a ride but still have the same result. The only difference that I did notice is that the engine would stall after completely letting off the throttle. Out of curiosity I reconnected the 16 pin connector so I could observe the tach. With the trans in park and the engine warm the engine starts breaking up at approx 4900 RPM. Don't know if this info means anything.

 

That's why I'm thinking the speed limiter built into the speedo is causing the problem. We were lucky in the shop to have replacement speedos occasionally to swap out and see if this was the problem. Shows that operating rpm is 6000 rpm. Manual I have throws in the x2 and efi also so doesn't give a lot of checkout info. I'll keep checking through it and get the ignition specs also if it shows the resistance values. Could be a coil breaking down when warm or other ignition problem that could be imitating what a faulty limiter would do. OPT

 

OK. For whatever it is worth (whether helpful or not), When I changed the spark plug I did notice a difference but it was very short lived or so it seemed. Maybe 30 minutes Vs. 5-10.

 

I'll get back with any ign specs I find. OPT

 

Pulser coil w/r to white (185 ohms ) w/r to ground (open)
Charge coil yel to yel (0.43) yel to ground (open)
Coil primary (0.11 ohms)
Coil secondary (6.7kohms)
See if you can eliminate this as a problem. OPT

 

OPT,
Pulser coil R/W I have 195 ohms. R/W to ground is open. As far as yel to yel, there are 3 yellows that come out of the flywheel housing and run up to the ECM (I think). Are they the yel wires to test? If yes I have 0 ohms acros all 3. Can you please clarify if the 3 yels are what I should be checking? Also not sure how to check he primary and secondary. Are there specific color coded circuits or do I need to go into FW housing?