My 13 year old son bought a used Chinese quad with a Lifan 110cc engine. He has little to no engine knowledge, and I have enough to know what questions to ask, so between the two of us it's been an education.

The issue he's having is keeping it running. Regardless of cold or hot, the engine will idle (with choke) but when he thumbs the gas, it's bogs and quits. I showed him how to adjust the idle, it seems to have no bearing on this issue. I didn't want him messing with the mixture screw so I didn't show him that. I understand from various online reading that the correct adjustment should be 2 1/4 turns out. I'll be checking that myself to make sure it's correct.

It has a new battery. Fresh gas, clean air filter. I told him to run it with the gas cap loosened, thinking it was maybe a venting issue (long shot but easiest to try first). The next step would be the fuel filter and removing and cleaning the carburetor and pilot jet.

I understand that they are the next steps but what we are looking for is the actual step by step on how to do it. He was all about removing the filter, until I mentioned that the gasoline is going to p... I mean, run out of the tank. Lack of knowledge is going to have him messing up more than repairing, and getting more discouraged instead of building his skills.

If someone could direct me to a place where step by step direction could be found (either video or pictures) or if someone could actually walk me through this, that would be fantastic, and I would be able to pass on some knowledge to a kid who is desperate for it.

Thanks for the patience and for your help. This seems like a great forum with a ton of people willing to share what they know.

 

Do not alter the mixture screw until you have cleaned out the carburettor. I am sure there will be lots of videos on how to do this, if there isn't a tap on the tank to shut fuel supply off, you could pinch the pipe flat with a pipe wrench or plug it to stop the fuel flow, or run the contents of the tank into a can, while you work on the carb. I don't know if this video is any good, just googled it as an example.

 

Merryman is right on...sounds like it needs a cleaning...sounds like the idle jet is clear (idles), but the main is clogged...a bit odd since one has a much larger orifice than the other, but anything is possible. While in there I'd confirm the jets and ensure they are stock or close to it...Have had many a folk clean/rebuild carbs several times without noticing what they were cleaning didn't belong in there in the first place...

 

Clean the carb.

And youtube all the parts to clean.
float needle
Two "jets"
The jets have tiny holes in them; maybe 22 guage wire size or so. I like to work something through each hole, but do no force it, and go easy.

You have to disassemble it entirely -- keep track of the parts. They are small, and easily lost or damaged.

But yeah, clean the carb. I had a 2007 110 (107) youth atv that ran lousy. Finally, I did the research and cleaned the carb. Now it runs wonderfully. Unfortunately I let mine sit outside all those years so it had numerous other issues, so I'm steadily putting it back together again. But once I had a clean carb, the engine purrs.

Anyone know how to get the rear disc brake to work again?