After riding for about 30-45 minutes my sons 90 started cutting out just above idle. idle no problem but give it gas and it cuts out. we were riding in tall grass, no mud or water. the stator was not caked up with anything. still leaning toward cdi or new stator? first part of the ride we had no problems at all.

 

Welcome to the forums.
I'd give the carb a good cleaning to eliminate that aspect.

 

On top of what LT80 mentioned take the plastic stator cover off and blow out any dust around the flywheel and pick up coil. Better if you can take the flywheel off and clean it and the stator up.Found plenty of them coated with dirt. These early Polaris 2 strokes were notorious for stators over heating/shorting out even with out mud or water involved. Just not a good design on covers being able to cool the stator area and seal them off from the elements at the same time.

 

would a replacement stator remove the problem of overheating? factory or aftermarket?

 

Don't just swap out parts until you test them.From some of the reports a lot of cheap Chinese aftermarket 30 buck stators have given some customers problems. I'd stay with oem or Ricky stator if the stator resistance specs shows weak.Worth 5 bucks for a service manual to help you find the problem if it's not a carb problem or fuel related.Plus can help on future service /repair problems or questions.2005 Polaris Sportsman 90 Service Manual PDF Download

 

You didn't mention anything about overheating.
have you cleaned the carb yet?

 

Haven't cleaned carb. It is new with new fuel filter, fresh premix gas (non ethanol) 50:1. Deleted oil injection. Don't think it overheated. Will start up but not rev up much over idle.

 

Haven't cleaned the stator yet. I need a puller. I do have the service manual just haven't tested the stator yet

 

IMO, there is no reason to go further untill you clean the carb and eliminate that aspect.
New carb means nothing. Filter either seeins that the dirt usually comes in the vent.

 

Just do as LT80 suggested and clean the carb or a carb kit first(since it does at least idle) along with checking/changing the plug,cleaning the air filter,etc! Eliminate the obvious/easiest first and if cleaning the carb and checking that it's getting a good fuel supply doesn't help with the problem,THEN move on to the next thing to check off the list.It's just a process of elimination. I just give all areas that can be problems from what I've experienced with these little ones,but don't let a lot of different thoughts over whelm you. Like they say,Rome wasn't built in a day..