Fuel in filter looks boiling

[VIPScoot]

At first I was having problems starting my VIP after it was running fine. Like it wasn’t getting fuel. When it wld finally attempt to turn over I would have to turn the throttle wide open for it to finally start. Now I just won’t start at all. It’s getting plenty fuel, good spark, clean jets. What I am noticing is that while cranking over the fuel in the see thru filter looks like a boiling pot of water. I’ve never seen this before. My question is this.... could this be a “Petcock” problem? I pulled off the vacuum line and noticed a wee bit of fuel in it. Any ideas? . I know there is fuel going into the bowl cuz I can drain it out of the overflow line