[jhirasak]

I would not recommend drilling the exhaust jet since it contains a check valve and any trash from drilling could affect the ball seating. As I recall, the exhaust jets were not very expensive.

There is another advantage in having an open exhaust jet instead of the standard 00 closed one. With current gas formulation containing some ethanol, there is the chance of fuel percolation in the accelerator pump chamber causing fuel to drip out of the pump nozzles and into the throats after hot shutdown. Having an open exhaust jet allows any buildup of pressure in the pump chamber to bleed back into the fuel bowl instead of causing fuel to drip out of the nozzle.

With my Webers which came with a 00 exhaust jet, I changed to 0.35 and then to 0.50 which eliminated the fuel percolation problem while still providing enough fuel delivery to avoid stumbling during acceleration.