2002 400ex turns off when you turn choke off
 

hello so my atv sat for like 7months and i started to work on it again and i took the carb apart cleaned new plug (i did gap it the spark plug is already jet black) oil and gas. i started it up and it will only run if you hold the gas and have the choke on as soon as you turn the choke off it kills its self so i took the carb apart again and checked everything and it is still doing the same thing if you hold the gas sometimes it will hold the idle and it runs fine and then other times your holding the gas it will run like crap and misfire alot. if any one has any thoughts on what it would be please help

Fresh gas? If not drain the tank especially if you have untreated ethanol. May still have trash in the jets or openings or a worn float needle. No sense in having to go into a carb but once. Clean and blow out every opening and install a good quality kit on this 16 year old carb.https://www.ebay.com/itm/HONDA-TRX40...QAAOSw1x1UNCkT

yes its fresh gas and the carb i put in it is only like 1-2 years old

Chinese or oem carb? Either way setting up as little as the 7 months ethanol fuel can cause carb problems.Plus if that new plug is black already that could be part of it. A partially fouled plug can cause misfiring along with a float needle sticking,float level off no matter how old the carb is.. Have the jets to where you can see through them,every opening blown out. If you can eliminate the carb,plug,fuel,air filter and it still runs crappy,you may have other problems.

I agree with the above post. If the spark plug immediately gets black that is very wrong. If you can, tear down the carburetor and bring it to a power-sonic cleaner or some other powerful cleaner. Then take the carburetor back out, air compress the carburetor to dry, check if any parts need replacing, then put it back together.