Issue with Polaris Sportsman 500 - engine missing

[woodlandfarms]

OK, looking for some suggestions....

Got a 2005 polaris sportsman that is my farm quad. Worked well until this winter. Picked up a weird miss, in the upper range it just falls apart... under load even worse. Figured it was the carb...

Rebuilt the carb, adjusted the valves, new spark... Still is happening. Not sure where to look next other than ignition. Wondering if anyone had any thoughts... I don't think there is water in the pull starter... Not 100% sure until the cover comes off... It really feels carby the issue... Was wondering if my choke is leaking but it looked good (was not part of the repair kit of course).

Anyway, love to hear some suggestions as it is driving me crazy (or not driving me at all).

 

[Xfaxman]

Saw the thread title in Today's Posts and thought your engine was gone!

 

[MossRoad]

Saw the thread title in Today's Posts and thought your engine was gone!

Me too.... a missing engine is certainly an issue! :laughing:

 

[MossRoad]

Coil and plug wires would be next on my list.

 

[buckeyefarmer]

Saw the thread title in Today's Posts and thought your engine was gone!

What I thought also..

 

[woodlandfarms]

My father was an English professor and part of my living is made from writing and I still amaze myself how poor of a writer I can be.

 

[Xfaxman]

It dont make none diffrance on hear anyways!

 

[MossRoad]

It dont make none diffrance on hear anyways!

Spit take! :laughing:

 

[woodlandfarms]

Well, just as an FYI, I believe it might be the Cam. THey are prone to failure, and it sounds like what my engine is doing would be similar to the same issue. Apparently the cams for the engines do not have enough oil and the exhaust valves put a lot of pressure on the exhaust lobe, thus grinding it down. Will find out later this summer when I get back home.

 

[MinnesotaEric]

OK, looking for some suggestions....

Got a 2005 polaris sportsman that is my farm quad. Worked well until this winter. Picked up a weird miss, in the upper range it just falls apart... under load even worse. Figured it was the carb...

Rebuilt the carb, adjusted the valves, new spark... Still is happening. Not sure where to look next other than ignition. Wondering if anyone had any thoughts... I don't think there is water in the pull starter... Not 100% sure until the cover comes off... It really feels carby the issue... Was wondering if my choke is leaking but it looked good (was not part of the repair kit of course).

Anyway, love to hear some suggestions as it is driving me crazy (or not driving me at all).

A bad coil can cause the same problem. Works fine at lower RPMs, shorts out when high energy demands more power. Heat can also cause the same problem with the coil, or to the pick-up coil triggering the ignition system.

I'd look your ignition system over.