New to the site and hoping I'm posting to the correct forum. 2004 ATP Sportsman 500 HO with 650 hours. Stored under cover. Only repairs have been a starter solenoid and right front CV boot. Used mainly during hunting season fro travel to/from woods. About a month ago after riding about 20 minutes my daughter walked back to camp saying the quad died and would not restart. I walked back to the quad, checked the tank was 3/4 full, hit the key and drove the 1 mile back to camp. Arriving at camp the engine stalled as if the key had been turned off. It would not restart- bucked as if it was flooded. Waited 2 min and restarted without issue, ran a minute or two and died as if it was out of gas. To shorten a long story, replaced the fuel filter with a larger, see though filter. Did not resolve. Replaced fuel pump. Made sure I was getting vacuum on the suction port. Verified fuel flowed into the filter when the gas selector **** was on/reserve and stopped when the **** was in OFF. Same issue. Appeared to run until the carb bowl drained. To busy to check float so replaced carb this past weekend. Ran 10 minutes at 4k rpm through the neighborhood and then sitting in the driveway it died requiring a few minutes to sit before it would run long enough to get it under cover. Fuel filter stayed 3/4 full at idle or high RPM. This sure acts like a fuel delivery issue. New gas, filter, fuel pump, carb should eliminate fuel delivery. Sorry for the long post. Any guidance would be appreciated.

 

Since you're sure fuel flow isn't the issue,good flow,carb and tank vent lines open,plus you replaced the carb,issues may not be fuel related since it's doing the same thing with a different carb. If you haven't checked valve clearance I'd do that first as valve clearances can tighten as they get warm and cause running/starting problems. 650 hrs is quite a bit if they haven't been checked before.006 clearance intake and exhaust. If the valves aren't tight,the issue could electrical.Could be loosing spark as it gets warm. On this I'd get the cheap manual and go through the fuel,mechanical and electrical trouble shooting guides and checks.It can save you headaches and help narrow down where the problem may be.2004 Polaris ATP 500 Service Manual PDF Download When you solve the problem I'd spend the time and rebuild the oem Mikuni carb as it's a $500 quality carb versus some of the cheap Chinese knock offs that may or may not work right or be jetted correctly.Takes the same kit as the Sportsman 500.New Shindy Carb Repair Kit Polaris 500 Scrambler 4x4 03-05 500 Sportsman 03-410 | eBay

 

Thanks for the quick feedback. I called 2 dealers and both mentioned the same valve clearance issue. Restoring a '49 Farmall cub and trying to get ready for hunting season I just don't have free time so I took the ATV to the dealer. I will pull the cheap carb off and put my original back on as soon as it gets back though. Downloaded the manual so I have it going forward. Will be interesting to see what the dealer comes back with. $145 diagnostic fee applies towards any repair work.

 

$300 later the ATV is running fine after a valve adjustment. Now I just need to pull the new carb off and put the original back on.

 

I know prices have crept up since I retired,but this much for just a valve adjustment? I may pick my tools back up again..

 

Wish you were closer to Atlanta. Need to replace the rear master cylinder on the Polaris, do an oil change and grease all the fittings. I am in the middle of rebuilding a '49 Farmall Cub, need to replace the clutch on my '59 Ford 851 (currently for sale) and hunting season starts in 3 weeks.

 

Sounds like you have your hands full. Yes I still could adjust valves for ya,but I'm too lazy. Retirement has spoiled me and even my neighbors know not to ask me anymore..