In other circumstances, I have used Permatex Green Sleeve Holder to reinforce loose threads. It worked for me as long as there was enough thread left to get “adequate” torque on the bolt. “Adequate” is a sharp term, a “I’ll know it when I feel it” kind of torque.
It is essential that the bolt and threaded hole are absolutely clean. Clean both with spray brake cleaner and then first with isopropyl alcohol. Then place the sleeve holder into the hole and onto the thread. If you can, let it set for 24 hours. If you can’t, give it at least an hour.
Helicoil is the best option, in my experience. If it installs well, it’s at least as good as the original setup. I’ve lost count of how many carburetors I’ve put heliboil in.
