ORIGINAL: kersplat
In order to use "bladder pressure", you fill the bladder by the fuel line on the engine. Then you need to clamp the fuel line with something,"I use a hemostat". If you don't the fuel will simply gush out the spray bar before you get the engine started. When you prime the engine for starting, you are ready to start. When the engine starts, you release the hemostat and the engine will scream like you never heard before.
The needle setting is usually about 1/2 to 3/4 turns out from closed. Remember with this setup, the engine will not last long.[X(] With great engine speed comes short engine life. If this engine is the one with the nickle plated cylinder, It will mabe last 8 hours running like this.[
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Actually that was considered about average life for a 1/2A. Remember that runs were generally no more then 2 minutes with the average tank so you got a few years out of the motor to get that much time on it.
That said you really can get more out of them simply by keeping everything scrupulously clean, filtered fuel, 25% oil no less, and don't run it so lean it bleeds to death.
Dennis