Hard to start F1

[HardlyDangerous]

Does anyone else have a hard time getting their pocket bikes to start?

I have a customers bike in right now, I'm not sure the brand but it's a pretty cheap, 49cc , very basic ebay bike with dual exhaust,plastic recoil starter (I believe they said it was an F1)
It's brand new and it will NOT start on it's own.
It has great spark, getting fuel to the carb, choke and float level are ok as well. Everything looks to be perfect.
Pour a shot of fuel down the spark plug hole and it fires right up and purrs like a kitten and runs great. After running even a minute it will start until it's cooled off. Then same thing...
There appears to be no pilot or main circuit adjustments on this carb so how does one make this bike easier to start?

I was going to tell the owner just to spray a shot of fuel into the intake however it has a crazy plastic intake/filter that prevents spraying fuel into the carb without removing the filter.