I took it upon myself to cut the tube off inside the airbox of my trailblazer. Big freaking mistake. I have been trying to get this thing to run right for 3 days now.[ul] The only way it would run without sputtering was to raise the clip on the needle up one notch. But then it would run too lean -the tip of the plug was grey.[/ul] [ul]Next I install a 140 main jet (factory is 130). That got rid of the lean situation, but went right back to mid-sputtering. Its not BAD but it bugs me very badly. If you stab the throttle open it runs fine, but slowly open from idle to wide open and it will sputter at mid throttle. I'm about ready to put a FOR SALE sign on it and find me a ol' reliable 4-stroke.[/ul]Can anybody help?

 

Not sure if I can help but..... I dont know how the blazer air box is but I assume you cut the tube to get more air flow. If you actualy did get more air flow then you should of had to raise the needle (lower the clip)and or go to a larger main. which you did. In jetting your supposed to set the main jet first, 3/4 to open, then work backwards to set the needle 1/4 to 3/4 then pilot. Find out which main you have is best testing at 3/4 to open. check the plug so your not lean, it sounds like you know how to read a plug well enough. then start on the needle in stock position and test ride it, stay in the throttle position you are testing for (unless its running real bad). Check the plug for a reading. Also if you suspect its lean in a certain area pull the choke a bit to richen it up to see if it helps. if it does you on the right track, you need more fuel there. Change the clip accordingly one notch (lower the clip = more fuel). always test the same way and only make one change at a time. In jetting its best to have a sytem of doing things and write down results. its hard to keep track after a couple of changes. If the clips all the way down and you still need more fuel go to the next size main and test again starting with the needle in the mid position. If ya cant get it jetted right I would put it all back the same way you had it before the mod and make sure that that runs like it used to so you know that nothing else is wrong. Then try it again systematically. Did you make any other changes along with the air box? The mod doesnt sound like it would need more then a step up or 2 on the main (if at all) and change in clip position. Good luck.