I had it in an Associated RC8 when pulled I it out and discovered the problem.
After i pulled the idle screw out the slide would still bind and only seat completely with some force, like it has a tight spot. I used afterrun oil and keep working it back and forth tell it wasn't quit so bad. put it all back together and installed the motor in to a losi buggy. It stuck a few times Friday night making it hard for the boy to drive and i noticed fuel seems to be leaking from the slide boot and now it seems to constantly run fat.

I put my first B5 in my losi truggy and have had no problems.

I'm gonna pull the new B5 carb back out abd check it again to see how bad its still binding. I'll check the idle screw grove and try deburring.

Thanks
Chip