I have a 2003 Warrior 350. It has a K&N air filter and FMF exhaust pipe. I’m having trouble getting it to run smoothly. It does not idle great and stalls, hard to start. I have to keep the idle really high. It runs just okay at full speed. I get some popping out the exhaust sometimes. It also seems to run really hot. I’ve been trying to adjust the air/fuel mixture screw but that doesn’t seem to be helping or make much of a change. I’ve tried from ½ turn to 2.5 turns out. I’m now wondering if I need to change the jet(s)? I’ve cleaned the carb twice and that didn’t fix the problem. Currently my main jet is 145 and the small jet is 42.5 After doing some reading that sounds like it’s stock. With the air filter and exhaust should I try increasing both jets?



To me it seems as if it’s not getting enough gas.



If so what jet(s) do you recommend?



I’m in Canada in the prairies so it’s low elevation and 70f average temp.



Also, what should I do with the needle?

 

As a start, move the needle up one notch. That means put the clip in a lower slot. I would also bump the pilot jet up one, to 45. You should do these 2 things separately and then read the plug, but I suspect you need to do both.

 

Thanks. What about bumping up the main to a 150? Or does moving the needle up one notch make it richer? Moving the needle is like fine tuning between jet sizes? Is that a correct way to think of it?

 

Yes, moving the needle up a step-at-a-time is a minor adjustment. Changing the main jet to bigger makes it a lot richer. Sometimes you change the needle, too.

If you look at a new plug after running it for a few minutes, you don't want it looking too black or too light-colored

Warriors are great. Lots of folks want to F with the carb/muffler/filter. They work pretty well stock, IMO.

 

Thanks for the info. I'm not looking for a race quad. I just want it to run good and be reliable. These bolt on mods were on it when my wife bought it.

I also noticed I have a "power bomb" on the exhaust. Not sure if that will affect the jetting as well.

I'll try the 45 pilot first. then maybe move the needle, currently it's in the middle notch. then maybe a 147.5 or 150 main.