I recently purchased a 01 Scrambler 90 from a guy that had been sitting for 2 years in his shop with gas in it. I replaced the plug, fuel filter and put a 20$ aftermarket rebuilt carb on it. The oiler went out previously so I mixed some fresh premium gas with oil 32:1.

I have the fuel mixture screw 1.5 turns out from snug and the idle screw out a ways and it starts easily with the kick or electric start but runs for 2-3 seconds then dies. Before putting the rebuilt carb on it I attempted to clean the old carb and was seeing similar results except it would only start ether. Once I had the ATV moving though I could drive it for hours until it cooled down.

I have not tried to remove and clean the fuel shutoff switch yet. I was just wondering if anyone has suggestions for things to check tonight. I can put a video up later of it running also if that would help.

Thanks!

 

Did you check jets on the Chinese knock off carb versus oem? Should be a good fuel flow from the fuel line to the carb.Clean the cup and screen in the fuel valve. A lot of people overlook this plus check for any kinked fuel lines and tank vent lines.Lot of places lines can kink.

 

Thanks, I have not checked the jet sizes yet but I will look into these things tonight.

Also should this carb have a vacuum line? The carb I took off didn't have a vacuum line running to it. I have a hard line on a small brass barb from what I have seen that is the oilier and its unhooked anyways.

 

No vacuum lines.Small barbed fitting on the carb is for the line from the oil pump. If the oil pump is unhooked,and you're premixing the fuel,block off this barbed fitting on the carb with a rubber plug or it can draw in air and cause running problems.

 

I'd also pull the jets on the rebuilt carb and ensure all passages are clean...it don't take much to plug the idle circuit...

 

Thank you everyone! I will look into all of these items tonight. One other question one side of the Duct Hose is rotten so its just not a real good fit, what is the purpose of this? I found it on eBay but wondering what symptoms this would cause if any.

Thanks.

 

pic?

 

Air duct on the air box or one on the clutch cover? Either way both are for fresh air.Dirt Cheap Yamaha, Polaris, Suzuki & Kawasaki OEM Parts & Accessories – Cycle Parts Warehouse

 

35 - duct-11345-151-000 * 0450707

 

See if this manual can help you under stand how the duct works. Has an internal filter also.2003 Polaris Scrambler 50-90 Sportsman 90 Predator 90 Service Manual[1] - Documents