Learn from this: There is an interim Carb set up Briggs used between models on the 17 horse Twin II. It has a rare gasket my mentor had rarely seen over years and years of sales and service, and he's a cert. Mechanic. Trust me, this guy knows engines. Any way, This thing was vomiting fuel like no other. I had cleaned it, inspected it, several times. New fuel pump kit, dissasssembled at least 6times. This was a real stumper. Solution: where the fuel pump bolts to the carb there is a "hidden" vent that was plugged. It didn't look like a vent, but I persisted in "opening it" because I swore it was a casting mark or something, but was out of other options. Any way, The model is 42a707. type: 2238e1 code: 0003235a Feels good to finally solve this.