Thank you all for your responses. Dave also emailed Permatex, and they recommend High Performance Thread Sealant (56521). We will continue to investigate our options and hope to have it fixed soon.
I do have a fire extinguisher in the car — Daddy always carried one, and very early in my ownership I used that 40 yr old one for a carburetor fire. I now have a newer one in there. We have a local ethanol-free gas station, so I rarely ever use gas with ethanol in it, so hopefully that is not the problem.
We’ll miss everyone at the BASH…but future daughter-in-law’s bridal shower is important. 😀