Like title says, when I close the choke engine goes wide open throttle, what would cause this ?

I just bought this chinese 125 and the carb was overflowing I was told when I bought it so I opened it up, adjusted the float, cleaned the jets and put it back together, making sure the needle tube thing was in the slots, fired it up w/ choke on and let it run for a few minutes, jumped on it to take it for a test drive and noticed it was running weak, at that time I remembered I forgot to close the choke so I reached down closed it & all of a sudden the thing took off at full throttle & what a excellent time to find out the brakes don't work so anyways I was able to hit the kill button fast enough & stick my feet down before being beheaded by a laid over tree but I can't seem to figure this out, I have no a/f screw it's a plug & I've tried adjusting the idle screw from all the way down to about 4 or 5 turns out with no difference & yes I've tried flipping the needle 180 and even checked to make sure throttle was working & that cap screw was on tight so.

Any suggestions or recommendations on things to try ?

 

check for vacuum leaks? on your intake boot from the carb to the cylinder. check to see if the flange has an O-Ring in it and it is facing the correct way. that could lead to a big time vacuum leak. so your slide is in correctly. hmmm......

 

Ya that was my first thing, I took the carb off & found the main jet, or the little jet inside the big one, (needle jet) I guess it is called was totally clogged & I could not get it unclogged, I'm ordering a new carb just trying to figure out wich one to get, gonna measure intake tomorrow see if a 25mm or 22mm will work on this 125.

I'm thinking either clogged needle jet (wich don't make sense) because if it was clogged it wouldnt let any fuel out would it ? And it wouldn't make the thing run wot would it ? dunno, I know Ive shut gas off to engines before & they run wot for a second before they die but I guess we'll see, thx for the suggestion & I'll report back w/ my findings for others.

 

you're right. to me, if your main jet is plugged/clogged, it wouldn't get fuel to run except through the pilot/idle jet. for stubborn clogs that don't seem to want to be removed, i use an oxy/acetylene torch tip cleaner pack to rod out the orifices.

i still can't help but think that you have a vacuum leak. was the flange on correctly if it had one on the rubber intake boot? did it have an O-Ring that faced the carb? you may try pulling the carb out and leaving the throttle cable connected and stroking that and look inside to see what the slide is doing. surely on top of the slide the cable is still connected and the spring is working. what notch setting is the needle on up in the slide there at the E Clip?

 

i wonder,, could the folks that had the quad before you have tinkered inside the carb, lost parts to the jets, and then reassembled the machine and got rid of it? i have seen a 2 part jet before on some of these quads. i'm curious about it now. , can you post pics of the inside of the carb/jets? if not on this post, make an album under your profile as we can go look there also.

 

I decided not to figure out the problem, I'll spend more time chasing it down then need to so I just ordered a new carb, I'm thinking the throttle cable was kinked as I had this happen on my 110 today after cleaning the carb, eitherway this will put one more thing out of the equasion & at only $25 or whatever it's a small price to save a headache.

Thanks for your help, I will report any findings.

 

I fixed this today, Turns out it was a simple throttle cable adjustment, didn't see it was adjusted too far out to let slide close, had it fixed in 30 seconds. Put new carb in & did the exact same thing. Hope this helps.