Motor won’t stay running

Bewy said
Permatex #3 or #4 [ non-hardening & hardening ] would be good. A very old product but still works well.

the #3 is aviation form-a-gasket and works great in applications such as this. it's PN 80019 (4oz bottle w/ brush cap). i'd recommend this over the copper spray.

you could also use p-tex #2 or hylomar

just none of that silly-cone near the gas.