My 2003 Praire 360 just recently (today) started backfiring when I let off on the throttle. This winter it has not been ideling properly, it would only stay idle when the choke was on. Today I adjusted the idle and now it idels again properly (W/out the choke) , except now it also started backfiring. Do I need to bring it in for service or is this a simple quick fix that someone with no mechanical skills can do. Please help I use it to plow and it is snowing out. Can I still drive it?

 

I had the same problem as you..... hard to start, had to choke it fully, wouldn't idle unless it had 1/2 choke or it was warmed up...... My problem was i was to lean, I fixed it by stepping my jets up one full size ( from a 132 front 138 rear to a 135 front 140 rear ) I also turned out my pilot screw to 3 turns out in front and 3.5 turns out in the rear. Starts right up now and purrs like a kitten but roars like a lion when i hit the gas.[img]i/expressions/face-icon-small-wink.gif[/img][img]i/expressions/face-icon-small-smile.gif[/img][img]i/expressions/face-icon-small-happy.gif[/img] I am not as knowledgeable as some of the other guys on here but it sure sounds to me like you are lean. Try turning out your pilot screws first.... gives it a little more gas. Have you done any mods such as air filter, snorkle, exaust mod????

 

no modifications. I read your fix however I have no idea how to do any of that. I read in the manual how to adjust the idle using the screw/spiring under the carb. After adjusting it the machine began to backfire. It idles ok now just backfires. How do I locate/do all the other stuff you mentioned?

 

This may sound silly, but I saw a Praire 360 with pretty much the same symptoms, and
all it took to fix it was a new spark plug. Don't know if that would do it, but its a cheap
and very easy thing to try.

 

My 360 did the same thing. For some reason the spark plug was loose. A I put in a new plug and it went away. good luck. lively

 

Id start by turning the idle mixture screw out about 1/4 turn, that should make the backfiring stop , and make it easier to start and idle when cold.
http://www.atving.com/editor/techtips/carbclean.htm
see if this article helps you. The hardest part, is locating the mixture screw....I believe its on the bottom side,of the carb. Its a small brass screw.

 

Just to be simple try setting the idle up a bit and ride. It may just want more air.

 

adjusting the pilot air screw does help with idle and low speed operation. closed = lean, open=rich. they come 1 1/2 from factory. i set mine to 2 1/2 and it does help with cold starts and cold start idling.
do not play with your main jet. if you are getting backfiring through the exhaust, especially while decelerating, you need to adjust your valves. it will not hurt the machine as it is now, but you should get them adjusted. the factory settings on mine were too wide on the intake and too tight on the exhaust. properly adjusted valves will improve the overall performance far more than just asjusting the air screw.
2 hr job the first time you do it...probably 1 1/2 hr job once you get the hang of it.

it is supposed to be done at 10 hours, and then once a year. i would say that it about right imo.
my 360 ran MUCH smoother after adjusting the valves.