I bought a new 50 cc quad. Pocket bike style but a quad. Apparently was never started & was difficult to start when it did. Always has a fair spark & seemingly good compression. It is a YJ-47TD made by ZHEJIANGYONGJIANG Industrial Company Ltd., July 2009. You can pull & pull & ... It seems to only have 1 screw with a spring around it 1/2 way up the carb. What is this screw anyway ??? Is it the idle speed screw ? I noticed another screw on the bottom of the float bowl. Is this the air/fuel mixture screw ?? should I turn this in & then back it out 2 turns ? Backed out screw with the spring 9 turns, inspected ok. Reinstalled it to 7 1/4 turns. Had on 2/3 choke, 1/2 throttle & it DID start ! It surprised me when it did start, spun wheels on tailgate & shut it off quick. Never did start again. Not the kill switch - has good spark. Turned the screw in/out 1/4 turn from there but still no start. Also, clear tube part way up on carb always drips gas when fuel valve is on. How can I fix this problem ?? I tried to start with no choke, 1/2 choke, full choke, 1/4 throttle, 1/2 throttle, etc, etc ... Any help appreciated

 

I had about the same problem with a 50cc quad I have. For me it turned out that the float in the carb was getting stuck. Haven't found a real solution to this yet other than taking the bowl off the bottom and unsticking it from time to time.

 

Is the fuel leaking out a hose that goes a short distance and is open ended? That would mean that your float needle seat valve is leaking and the carburetor is overfilling (as happened to boblhedjesus).

As the carburetor fuel bowl fills up it raises a float which is supposed to shut off the gas keeping the fuel level correct. If you're overfilling the carburetor to the point that it is running out of the vent/overflow hose then the quad will never start up.

Do you have a fuel filter installed betwen the gas tank and the carburetor? If not, crud from the tank can get lodged in the needle/seat and keep the gas from getting shut off by the float.

 

Now what happens is it will start say every 20 pulls or so. It runs for 5-8 sec then dies. Have the screw on the exterior bottom of the float bowl backed out 2 turns. The other screw with the spring - idle adj I guess - is turned in about 8 turns - same as when I got it. It only drips gas 1/2 of the time. I do have the filter between the tank & carb. I think it may have some dirt in the carb somehow or need to set the 2 screws on the carb differently somehow ?? Any suggestions ?!?! Thanks

 

take out ur spark plug and see if it is wet or dry, dry means ur not gettin gas if its wet ur either flooding out ur motor or you dont have enough spark only guess i have, i'm working on a 70cc loncin with similar problems and from what ive been reading they all have similar issues. i would also wind in ur idle speed jet all the way, then back it out a turn and a half to 2 turns gd. luck