I have a K&B .28 engine with a cracked crank case that I repaired with J&B about 6 years ago. Many many flights later still hard as a rock and runs perfect. Are you guys using the J&B Quick[&o] or the regular set J & B weld. I threw my first and last tubes of quick set in the garabage. Anyways, as stated above just leave it as is as long as the needle valve assembly itself is not damaged.