how to adjust the air and fuel on a polaris 500

lilmunchiemn · #1 (**permalink**) 12-08-2009, 05:16 PM

Hi I have a 02 500 HO and this staring problem has been coming and going and now it has decied to stay. It cranks and cranks then lets out a huge backfire. I have good spark good compression. I then shot some starting fluid down the carb and it shot a fire ball out the exhaust. I belive it is a timing issue. When I contined to trouble shoot the bat. went dead. I put a charger on it and it started and ran fine. I let charge all night removed the charger wont start put it back on started took it off and wouldn't start again. I put it back on and started. once its warm starts every time. I checked the batter voltage and its 13.0 volts. What could be my problem I am beating my head on the wall.

**blueline15** · #2 (**permalink**) 12-08-2009, 07:22 PM

first off i see you are in minnesota, and of course right now it is very cold. carbed machines are very cold-blooded machines. what is probably happening is that your Air/Fuel mixture is way off. cold air is very dense (lots of air molecules) the carb is not able to make the extra fuel adjustment needed to get the A/F mix back to were it should be. basically the air/fuel mixture going into the cylinder is very very lean. and by saying once the engine is warm it starts everytime further leads me to believe there is nothing wrong with the air other then its not jetted properly for cold weather starts.

you really only have two options to fix this.

1) you can either re-jet your machine so jetting matches average temps seen AND your elevation

2) this is how we get our carbed machines started at the shop in cold weather. first, put it in neutral. second, hold throttle wide open, third, start cranking it over. holding the throttle wide open while starting will allow you to get the most fuel mixed with the air and it should fire after a couple cranks. you will probably have to feather the throttle until the motor warms (~2-3 mins) up because it probably will not idle when it is cold.

as far as your battery issue. sounds like it is toast. after you charge your battery and it starts the machine once, but not a few mins later it usually is a sign it is done. charge your battery fully and take it to a shop to have them load test it. takes only a few seconds and will tell you if you need a new battery or not

**Bruce!** · #3 (**permalink**) 12-08-2009, 07:34 PM

And welcome to the board!

lilmunchiemn · #4 (**permalink**) 12-09-2009, 08:51 AM

it started doing this in the summer and its in a heated garage.

**blueline15** · #5 (**permalink**) 12-09-2009, 09:30 AM

hmm.. okay, do you know when the last time the carb has been cleaned? it sounds like it is not getting fuel. has the machine sat for any length of time longer then a week without use?

atvjunkie821 · #6 (**permalink**) 12-16-2009, 07:28 PM

My buddy down the street had that same problem. There was a recall on the CDI or spark controller or something. Had it fixed no charge by dealer and has never missed a beat since. I will ask him tomorrow and get back to you.