1987 Honda Prelude "gas flame popping" Questions

flame came out of the side of battery. Left car overnight. Next day put a new battery on car and it was fine....until about 4 days later. Stopped at a store and came back out and car would not start..

...flame up into the raw fuel charged intake, causing the explosion or POP under the hood. The symptom I had was rough idle, stumbling / popping on acceleration, which got much worse as it warmed up. ...