Need HELP with Chinese ATV

[180splitg3]

Hey guys. I purchased two Chinese coolster 125 cc ATVs for my boys about two years ago. One of them runs great, never had an issue. The other one has never run well - pretty sure it's a carb problem. I am looking at just buying a new carb but am looking for recommendations on what to buy for it.

I tried to adjust the carb that came on it and have had no luck. The machine starts but won't stay running. Also, when I give it any throttle it almost dies - you have to really feather the throttle to keep it going. Once you get the rpms up a bit it will go OK but then you let off the gas and it dies. I only run 91 Octane fuel without ethanol so I don't think it's a fuel quality issue (use same fuel in the other machine). The carb it came with had tamper proof screws that I removed to adjust the float level but that has not helped. If I turn the idle speed screw way up it will keep running but then when you shift it into gear the high idle makes it dangerous for my son to shift.

Anybody have any suggestions on how to fix it or can recommend a replacement carb with adjustability? From what I've seen the carbs are pretty inexpensive. Thank you for the help!

 

[NV HUNTER]

You will need to take the carb off and clean it. Clean all the jets.

 

[Kalin s]

Can you post some pictures of both sides of the carb it has on it now?

 

[BeaverHunter]

You will need to take the carb off and clean it. Clean all the jets.

I was thinking the same thing. My Yamaha had almost the same issue the op is stating and cleaning the carb and all the jets was the fix.

 

[180splitg3]

Thanks for the advice guys. I'll try to post a picture of the carb tomorrow...

 

[Gunnersdad49]

I’d also check for vacuum leaks while you are tinkering.

 

[shtrbc]

Bottom line is, it's not getting enough fuel. May even "run" with the choke on or partially on. Like previously stated, a good thorough cleaning first. My experience with small engines has been that " a good cleaning" is not just spraying it with carb cleaner. I would try to find someone with a ultrasonic cleaner or a old school carb dunking setup with nasty, non-earth friendly, carb cleaning solution. The problem with these carbs is that the air bleeds and orifices are so small that the smallest piece of dirt or sludge from ethanol fuel causes problems. The ultra sonic really does a great job of cleaning this stuff out. Also, on some of this cheap, Chinese knock off stuff, I have seen parts mis-machined or features not machined correctly at all. IE..someone forgot to drill a hole etc.. Great question. Common problem for anything that burns gasoline these days. Best of luck!

 

[tt_johnsclist]

I’ve been down this exact path several times. For the price of a new carb just order one on Amazon and see if that helps. Good luck!


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[Wapiti1]

The idle fuel circuit is plugged. It may or may not be accessible for cleaning. Good carbs have removable idle jets, or access hole plugs so you can clean them with a wire. It could be plugged from dried fuel, or from dirt in the fuel.

I would be inclined to do as suggested above and buy a new carb if they aren't expensive. Clean the original as a spare. Put an inline filter in the intake line if it doesn't have one. Drain the carb before storage.

Jeremy

 

[180splitg3]

Update - purchased a new carb from Amazon for around $16 - all problems are solved! Runs much stronger than before and idles well. Wish I would have done this sooner. Thanks for your replies!