Hi Finn,
I gotta vote for initial timing set wrong.  I, and many others, have set the distributor off by 1 tooth.  It will sometimes start, sometimes not.  If it does start, it will run really BAD.  Check compression first to verify that the combustion chamber is sealing OK.  If you suspect the carb, just give it a shot of gas dirrectly into the carb throat.

Good Luck
Ken Powell