79 beetle wont start

I bought a 79 beetle conv. with 48000 orig miles and fuel injected. It ran for two summers fine. Now I am ready to put it back into storage and it wont start. We had starting issues earlier this summer but charged battery and it fired up. Now charging the battery wont do it. Lights and everything work after battery is charged for long time, car turns over but no start. It has gas and I checked the plugs and I have spark. It just keeps turning over and nothing. Any ideas? Thanks.