Cute video
Shame she did not use the vacuum on the brake tester as well
One problem with the fuel tank test is if the carb has a return line then the tank should hold around 7 psi before it vents some pressure off
What she showed only applies to systems with a single fuel line from the tank because those carbs are not pressurised
She should have also tested the tank in vacuum to ensure that air can get into the tank because if air can not get in then fuel can not get out .
The difference in price between the brake bleeder / tester she used and the full pressure / vacuum gauge is about $ 30.
This is the cheapest gauge you can get
Rotary pressure tester
Then go to a boat shop & buy an inline pressure pump bulb because it has hose fittings at both ends
Thus one way it is a pressure tester , put the hose on the other end & it becomes a vacuum tester .
Go to a golf shop ( or driving range ) and buy a packet of golf T's to use as hose stops, or have look in the gutter you will usually find dozens of them there .
One cheaper still is to just use the in line fuel pump bulb , a T joint and a cheap pressure/vacuum gauge from HF , probably cost about $ 10
Interesting video just the same , probably made her $ 500 in royalties off face book .