Oh wow, I had forgotten about this thread, sorry!

I tried the pump, I tried the large fuel tubing, I tried pinching off one of the exhaust tubes. Eventually, I gave up on the big ST and converted to a 40cc gas engine from BCMA. Now, I was told I would not notice much of a power increase, if any, but that was certainly incorrect!

Sorry, I tried pretty much everything and eventually decided that I would just take a loss and sell the engine on Ebay. I do miss being able to start on one flip, but it's all a trade off... Fuel is much cheaper now =)

Good luck to everyone else out there who has the big ST's. As far as I can tell, if order a ST, you have a 50% chance that you'll get a nice running engine out of the deal. That's been my experience thus far, after having had four of them.