Hey Toriy, thank you for the advice. I checked the air gauge and it was good, and i fiddled with the air valve. no luck.
However, I believe I found the solution. Prior to my testing and trying to resolve this, whenever I would restart the engine I would prime the cylinders several times and could never get the engine to start. I think I was flooding the engine or inducing hydro shock. I tried restarting twice today WITHOUT priming the cylinders, and the yak started both times without problems.
It should be noted that I did prime the main line to get the fuel pressure where it needed to be, but again, I did not prime the cylinders.
I am not sure if this will help anybody else, but I am happy that I have learned this, it was such a simple solution that had me stumped for days.
MisterMac的帖子在Restarting the Yak.中被标记为答案