well I own a 2000 400 foreman, and have since new
;ast summer, ot one before, I started having running issues
to the point I took it to a dealer who had it for almost 3 months
they rebuilt the carb twice, played with thsi and that
and in the end, it turned out to be the CDI(sure the carb needed a good cleaning but??)
they used a cheap after market CDI, adn a few months later, it died, and I had to buy a new CDI< this time I went OEM

which I should have the first time
that said,
if your atv is sitting for longer periods of time, it could simply be the gas, and , bad gas will dirty up a clean carb
this ethanol in the gas today will leave behind a varnish on all parts of a carb, jets and so on, and MOST simple cleanings does NOT remove it
so unles you are 100 % sure your getting it 100% clean
you can rebuold and spray out that carb a 100 times and its not going to work right
also, how clean is your air filter??
how clean is the inside of the gas tank?
if you don;t know these things, I suggest you start there
same witha good new spark plug
what does the old one look like, running rich, or lean?? or??? there are a some great HOW to tips on cleaning, boilinga carb CLEAN, do a little searching and you shoudl find the links to them
just make sure you remove any plastic/parts that heat might effect!

good luck, and welcome to the site

 

welcome to the forum.
sounds like it may have jumped time

 

Yea I recently bought a atv tht had been sitting for over a year. The gas thank was the worst couldn't even use it. But after a new one of those I boiled the carb in lemon juice. Rich450es had the story on it but it worked better than anything I have ever done.

 

Thanks guys for the warm welcomes,
So I pulled the spark plug this weekend, and it was black and the top of the electrode was white. The black/soot means it is burning rich, right? Also I am not sure why the electrode was white, any thoughts on that?
I also pulled the carburetor, and I am going to do a deep cleaning on that, based on mrbb's advice. I am also going to clean the gas tank really well, but I'm not sure what would be the best way to clean it. Any suggestions?

 

bst way to clean a tank is to remove it, and dump it all out, them flkush it good
, conmpressed air can be a help, but if it has settlement on the bottom, you might need to break it all free and flush with something that will clean better! there should be a screen in it also, make sure that is free and clean
and LOOK to see if there is any IN line gas filters, some folks added them, aa factory they didn't have one
and them filters can cause issue's with running too, seems many don't let the flow go thru with enough gas
also check to make sure the peacock valve isn't blocked at all too while its all of!
starting anew, can help rule out proplems down stream
good luck, and keep us posted!

 

Ok so i have replaced the spark plug, cleaned the fuel tank, and cleaned the carburetor. I put everything back together got it to start up without chocking it, since my chock cable nut is broken and will not thread into the carburetor, which I learned when I was putting everything back together. When I started it, I had the air filter box lid off and, I realized that the majority of the air being pulled in through the carburetor was being pulled in where the choke cable is normally connected. When I put my finger over the spot where the choke cable is threaded into the carburetor, the engine begins to die. Any suggestions why the air is not being pulled through the air box/air filter like normal?