it is a BIG no-no... in fact, it won't even work. when you push fuel into the tank via the pressure line, the air in the tank has to be released somehow. the only problem is that it can't, and instead you will just push fuel out the carb and really flood the engine in the process. doesn't matter how you try, you won't be able to get more then an ounce or so of fuel into the tank anyway.