Help!!! Also I have just flooded my AC 250 and since I have drained all fluids (oil, gas) and added fuel drier to new tank, I have took apart and cleaned entire carb!
Still Idles funny, it will start, then it will idle a little high, then it slows idle and then it will switch low to med idle every 10 seconds or so.
When I take off the air filter, it idles a little better, with the filter on I must idle her up about a turn or so.
I am going to get a new air filter.

Also the atv has backfired ever since I bought it, if you go down a hill in first or run it really fast and let off the gas. what is this?

Please help I am really desperate!!!!!

Jt
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Vewdew had an idle problem like yours...he found out that there was a hole in one of his carb boots I believe. You might want to check yours.

 

The backfiring after letting off the gas is usually (9 out of 10 times) a mal-adjusted idle mixture screw, which can also cause your idle problem as well. The idle mixture screw is located under the carb, just in front of the bowl. Typically it would be around 2 to 2-1/4 turns out from fully seated. Check its adjustment - turn it in 'til lightly seated, counting each turn, then back it out 2 full turns, and try her out. Move the screw 1/4 turn one way or the other to find where best idle is achieved without the popping after letting off the throttle. 1/8 turn can make a difference, so it'll take a little experimenting to get it just right. I've never had to take screw out more than 2-3/4 turns, never less than 1-3/4, so you should end up somewhere between here. DO this with a good clean filter installed. Also, remove the plug on the under side of the muffler and blow all the crap out with a quick ride first.

 

No hole in the boot, just installed incorrectly. I found that installing the boot on the carb side first helped me. Then installing the airbox side. May not be your problem, but worth a quick look.

Mark

 

Got it fixxed (at least 99.9% of the time) Listen up!

This info kills almost everything I have read on this board:

I live in the ohio valley by a river, humid climate at about 560ft above seallevel, tempature varies from 37f-90f.

1. I have been told to clean jets with a strand of a braided copper wire, and you wouldnt beleive the power restored from doing this!

2. I have opened the top half of my carb, located the choke assembly (front most little hole, smaller than an eraser head) and added WD-40 to that and moved the choke many times to loosen it, then there is a little moveing part in there that gets gummed up and controlls a small choke like function this causes a little backfire.

3. Fire up the engine (with carb top off, it will) when running quickly give it 1/4 idle and spray a little WD-40 on everything useing the mist tip ( this lubes up carb from a little water corrosion )

4. reassemble whole carb then take out spark plug and clean spark plug thourghly

5. check air filter while engine running take off and see if it idles up a lot if so new air filter needed or cleaning/oil required.

! ONLY If above Dosent Help --> there is a screen behind the aur filter before 2001 there were 2 screens if there are 2 and ONLY if there are 2 cut one out (ask your local dealer about this if conserned it was a service bullitin) 2 screens caused too much air blockage

This is the most I had ever herd from a dealer and all it took was a purchase of an air filter for 24$