So I have this really sweet Evinrude 4hp motor. 2 stroke 2 cycle. Model 4636M form 1976. The other day I was cruising into Clipper Cove and the motor started having a weird putter to it. Right before I landed the motor turned off with a "clunk". Now the pull start won't rotate the rewind starter/magneto cover. I can rotate the in reverse and when the pullstart gets it back to that certain point it won't go past it. But up until that point I can tell that I am getting spark and compression....Just not enough to get it going. what got stuck..or broke?