Anyone have any thoughts on what would cause a 2004 Polaris Sportsman to only run when choke is on slightly? As soon as I push choke in all the way the bike stalls.

I've run Seafoam and other fuel stabilizers through the gas. I changed the fuel filter. I changed the spark plug. I ran it with the air filter off briefly to see if it was airflow, and the filter looks clean anyway. I even rev'd it very high and then closed off the air intake to flood the carburetor and then let it sit. Nothing is helping. I tried to turn the throttle screw to up the idle and no help, seems to just runs hotter. So I pulled carburetor off and cleaned it but wasn't really any gunk or dirt except on the main needle, but wiped all that off and still runs only with choke slightly out.

 

Still sounds like you have a pilot jet stopped up. Seafoam or any other carb cleaner may not help that as you'd have to physically clean any blockage.Only running on choke is a good indication of that or something else fuel/carb related. To rule out a fuel pump,pull the fuel line from the carb and crank the engine over. Should be a steady stream of fuel.If you have to pull the carb one more time install a new carb kit and make sure every passage is blown out. This way you can at least eliminate the carb.Shindy Carburetor Rebuild Kit - Sportsman, Scrambler 500 2003 2004 2005 Carb | eBay

 

Thank you old polaris tech. Here's what the fuel flow looks like when cranking it over. Is that good enough flow?

 

Weak. Looks like time for a new fuel pump. That would be the reason also that you have to use the choke and not a stopped up jet problem. Too cheap to rebuild these pumps. Plenty of them on ebay and amazon.US Ship New ATV Fuel Pump For Sportsman 325 1999-2000/500 1996-2004 | eBay

 

Ok, old polaris tech thanks! I plan to buy this one US New For Polaris Sportsman Fuel Pump ATV Replaces 2520227/325 400 500 600 700 but can you tell me if this will this work for Polaris Sportsman 500 year 2004.5 (made in second half of the year)? It says only 2004 so I'm not sure what Polaris changed on the 2004.5 model from the 2004?

 

Pumps are all the same whether used on a 325/330,400,425,500,600 or 700 carb model. Just noticed after I typed this that the description even says that. Plus to save you some frustration,if you ever need hard parts order for a 2005 Sportsman 500 HO. That's basically what the 1/2 year model is.