I recently purchased a 72 Evinrude. I used it a few times and it always started on the first or second pull. Recently I took it out, and ran the engine for several hours and it ran great. I came back later the same day, it started on the first pull, ran for a couple of seconds, died, and hasn't started since. I'm not much of a mechanic but verified that I was getting fuel to the carb, ensured I was getting spark, and then did a carb rebuild on it. It still won't start. In fact, it doesn't sound like it has any interest in starting. I'm not sure what to do next. Any ideas would be much appreciated.