I just purchased my son a 70cc atv-chinese..brand unknown...after cleaning up the carbs and putting it back together...i got it to start.... but as soon as it starts up..if I let go of the hand brake..it will go. I noticed that the choke cable does not push all the way back in..when using the thumb control..i see the lever on the carb moving up and down ..but nothing changes. The choke cable actually pushes out of the holder when trying to push it all the way to the right. Also while holding the brake and then sliding the choke to the left..nothing happens...the engine does not rev any higher. It's almost like the choke is all the way on all the time. I am by no means a mechanic but I am trying to fix this for him. Can anyone help me figure this out.

 

where the throttle cable goes into the top of the carb, is the slide in there correctly? i presume so cause you say it starts but doesn't rev up. SO, when you put it back together, is the return spring doing its job inside the slide?
choke cable, did you take the choke out of the carb when you cleaned it? is the cable still connected to the choke element? i'd check that first. after the quad is warm, the choke should try to kill the quad.

 

I am not sure how to check if the spring is doing its job as if I take the top of the carb off to look..i will not be able to tell if it is compressing right. I know when i push the throttle lever...the pin did move up and down before i put the carb back in place. I did not take the choke off when cleaning the carb. Funny thing is...a few days ago..I wasnt having this problem with the quad taking off and now all of a sudden it is ...but I didnt take anything apart since then. Could the plunger from the choke be stuck? Is it worth trying to get it out or easier for a novice like myself to just buy a new carb and start from scratch. This is my first time tinkering with anything like this so please excuse me if I need extra explanation.

 

not a problem. we started out just like you. we tore stuff apart so we could learn about it and then put it back together to see if we got it right. it's easier to do yourself, not that hard, rather than pay someone copious amounts of money to do the same thing. yes, you can unscrew the top part of the slide and then actuate the throttle and you should see the slide/needle actuate up/down. just make sure you put the slide in correctly. you should see slits/grooves/guide ways on the slide. then look down in the carb's throat and see the ****/guideways, one is short, the other is long/deep. the slide goes down all of the way into the carb. if not, it'll be at a high rev when the quad starts. if it is set to the correct position, it'll idle as normal.
as far as the choke plunger, you should be able to unscrew it out of the carb and then actuate the choke via the switch/cable and see if it extends/retracts the plunger.

 

So I was taking apart the carburetor to check the spring and cylinder when the retaining clip for the needle popped out and landed god knows where? I can not put it back together without this piece...right? Do you know of somewhere I can buy just this small clip..or do you know someone on here who might have some. Please help so I can try to fix this thing once and for all. I have found the W-like clip in many rebuild kits...but none by itself.

 

local cycle shop, automotive parts store (O'Reillys, autozone, advance auto). tell'em you need an "e-clip" . take the needle in so you can match it up and make sure it fits. buy 2 so you'll have a spare

 

ok..so took carb back apart and pin needle spring is doing fine...lifts when throttle pushed..retracts when released...when driving atv...quad does speed up with throttle pushed..slows down when not pushed. Choke flap seems to be ok too. But still..after starting atv and releasing hand brake...the atv takes off....i am getting very frustrated with this thing! Is it just better for me to purchase a whole new carb and choke mechanism..or will that probably not fix the problem.

 

so this is an automatic (CVT) quad/semi automatic? no gears/gear shifting, just gas n go? adjust the clutch. i'll PM you a guide if yours is similiar, it may apply.

 

So i tried to turn the screw counterclockwise to adjust the clucth but i never feel any tension...its like the screw will just keep turning unless i secure it down with the nut. with the nut off just to see..it doesnt look like the threads are catching anything...the screw will almost turn all the way out..but then is held in by something...no matter which way i turn it...the the only way to keep it from turning is to tighten the nut down on it....there seems to be a small o-ring at the base of the screw.