2000 Trailblazer rough idle/sputtering

[psavas]

Hey, newbie here!!

I just bought a 2000 trailblazer 250, and man that thing is fun! I have had snowmobiles forever and love 2-strokes. The guy before me through a weisco piston in added some fox rear suspension and it is in really great shape.

I have a couple of dumb questions... The thing runs great but sputters hardcore almost like a backfire on idle and takes a couple seconds to come back down to idle after revving. I checked the plug, replaced it, checked air filter it's ok. He removed the oil injector and now i just premix, which is fine i think it's better.
However, I don't know if he did it right, or if he did why is it backfiring and not running smooth!? What should I look for? also if I leave it idle for about 30-40 seconds it will bog out and die. It run's great while riding, great power, great acceleration, no bogging when i romp on it.

Any help would be great !!

Perry

Ok so I looked around and this is what I found. Tubes 1 & 2 are skinny and run to carb, both have been cut and are just sitting there with no cap or anything. Tube 3 is a little harder to see, it's the thicker yellowish one that runs to the trans. That one is also cut and just sitting there..

Any comments on what these are and should I plug them !?

[crpowell08]

I believe the tubes are vent tubes And are supposed to go to a fitting tee and valve (vent check) but I am not 100% sure I got tubes on my 99 that are from the carb not hooked to nothing too and the parts manual shows them.

[galaxiedan]

Sounds like it might just need the carb cleaned. It doesnt take much to foul up a carb. Float level might be too high causing flooding at idle?

[blueline15]

agreed. you may need to pull the carb apart and give it a good clean. hard to say when it was done last, and they can and do get dirty fast. and/or there may need to be some minor adjustments made too, within the carb.