It turns over and runs fine. If I drive it for a while it will not start back up unless it sits for 15 minutes or so. The spark plug wire was loose at the cap.vvI replaced the spark plug wire and cap and that didn't help.

 

Start at the fuel supply first. Pull the fuel line at the carb and crank the engine over. Should have a steady stream of fuel if the fuel pump is ok. If the stream is weak or trickles out,replace the pump. Also check that the tank vent is open and not kinked.If the fuel pump is ok,carb is clean,all jets clean and open,problem could be an electrical break down when it gets hot. Check that you have good spark when it won't crank right back up to eliminate that as a problem.

 

I don't get spark when it is hot. I do when it is ambient.

 

Then sounds like you need to go through the no spark troubleshooting checks in the manual. Plus resistance check on the stator exciter coils and pick up coil.Pick up coil resistance on all the older ones was 97 ohms.Could be a cdi problem also but you have to eliminate the stator,coil,pickup coil,switches,etc first. 2001 Polaris Sportsman 500 HO Service Manual PDF Download

 

Now it won't start at all. I started at the spark plug. No spark. Decided to try with an old spark plug out of a car I had on hand. I got spark. Bought a new spark plug and I don't get a spark. The old car one has spark and the new one does not. Does this make any sense?

 

You originally replace the plug wire and cap.It was running good until it got hot. Have you gone through the manual as far as the ignition trouble shooting checks,resistance tests on the stator and coil? Electronics such as the cdi,stator or even the ignition coil can act up when warm then fail. Simple resistance test on the coil can "usually" rule it out. 0.3 ohms primary(coil tab to coil ground) 6300 ohms,coil tab to coil wire,cap removed. 5K ohms on the plug cap. If this tests ok,then go for the stator tests. If the stator,pick up coil check out ok,then that leaves the cdi module as the main suspect. 2001 Polaris Sportsman 500 HO Service Manual PDF Download

 

I have been going through the manual as advised. I am getting 2.3ohm of resistance from coil to engine ground. I cleaned everything up but that is what I get.

 

Touch your meter leads together to see if they zero out or show some resistance. If they show resistance,deduct it from what the coil primary shows. Common ground connections on the lower coil mount is the best ground spot to test. 10% +/- is usually allowed on resistance readings, but if over that,then sounds like the coil. If you have a shop nearby with a coil checker,they can verify if the coil is the problems also.

 

There was no voltage coming from the stator (new installed last year). I replaced it with a new one and it immediately fired up. It ran great for a couple of hours. Turning it off and on with no problems. Then it wouldn't shut off. Key out and everything. Turned the gas off and let it die. This morning I am back to square one with no spark.

 

AGAIN..Go through the electrical tests for no spark condition shown in the manual. It can be that new stator that may have crapped out or something else.First thing in the trouble shooting steps is to remove the black kill wire from the cdi to eliminate the switches. Then check for spark. If no spark go to the other tests,then head for the stator tests shown. Pick up coil on these older ones is always around 97 ohms resistance.Plus make sure the pick up coil gap is between 0.16-0.40 from the flywheel interrupter strip.