Timing marks being off could mean the carb mixture and idle are poorly adjusted. I had a Willys CJ2A engine that I couldn't get to run with timing set properly, but my mechanic cousin adjusted the carb and the timing came into line. He had a dwell meter and an idle meter which also helped diagnose the problem.
I thought the same as you at first. I had idle set way too high, but can't remember if mixture was way too lean or rich... Purred like a kitten after the tuneup.
-Boyo
