I was replacing the carburator on my riding mower that has 17.5 Briggs & Stratton intek engine. I must have tighten the carb studs just a hair too much. Now I have a vacumm leak causing the mower to surge off and on. I was going to use a helicoil kit to tap two clean holes for the studs. As i look closer at the Carb stud, the end that attached to the manifold....I don't recogonize what kind of thread it is. It is like a wide thread found on wood screws. see attached pic or a picture of this part via this link Carb Stud for Briggs and Stratton 31R977-0027-G1 engine. So I don't know if I need a different type of helicoil and or need to take a different approach. Looking any guidance or suggestions. Thank you for looking.