Carb is driving me CRAZY
 

Hello hello. Been working on an 02 MZ 50 Chinese garbage atv...https://cimg4.ibsrv.net/gimg/atvconn...ee9a3ba339.jpg
It is a 2 stroke. I acquired it from a cousin and plan to give it to my niece and nephew.... cutting to the chase.... It's in great shape mechanically, however I can't tune the new carb for the life of me. It will only idle with the air mixture screw set lightly snug (with the air filter off).... With the filter on, it will only idle with the screw out about 1/4 of a turn. This would make the carb too... Rich? I think? Would changing the air mixture screw to a different size solve the issue? I can let this quad idle for an hour easily, but once I wack the throttle, she bogs and dies if I stay on the throttle. Also, feathering the throttle does no good either. Yes the gas is fresh and no there are no air leaks. Also, it's a generic 19mm 2 stroke carb with an electronic choke. Hopefully someone can steer me in the right direction. Thank you and merry Christmas!

Welcome to the forums.

The mix screw should be out more. Closer to 3 turns plus or minus. The jets may look clean, but they can still have tiny pieces of dirt clogging them. A small wire, or if you have a really small brush that fits, will get out the stuff you can't see. Would also check the setting of the needle.


This may help some too.

some of those jets are hard to see.. took me 5 cleanings on one carb to find them all

Carb is spotless clean... If the air screw is bottomed out, my next step (I think) as you said would be the needle clip. Should move the clip up, or down on the needle??

Is the pipe plugged?

​​​​​​ Exhaust pipe? Nope. Everything is free and clear. I'm on the 4th carb over put on this piece of crap...the few that I've gotten to run great, i wind up with a puddle of gas on the garage floor the next morning. Tinkered with the float heights and just don't have the finesse or know-how to get it right.... She idles (very rich) with the air mixture screw from seated to 2 turns out or so.... But once I give her gas, she craps out.... I lowered the slide needle clip 1 not have which I thought would lean it out but I actually richened it up even more... My next step is to pull it apart again and raise the needle clip 2 not he's (1 higher than the factory setting).... Next step if that doesn't work is junking it. I'm extremely frustrated and fed up at this point :( wah.