I'm hoping that you post your findings when you get your problem solved. The exact same thing happened to my MVVS 26cc gas and I spent time trouble shooting it on three different days and could find nothing wrong with it.

On the third day I got the usual few feeble pops and was ready to give up. Then after a another long period of flipping with not even one pop, it suddenly sprang to life with no warning and ran just as well as it ever did. It somehow got well on it's own and has been starting on one or two flips ever since.

Since I did nothing to fix it I fear that condition may return again.