I have BN40I dual carbs and I have a hesitation problem when I get up to about 3000 to 4000 RPM. I checked the accel pumps on both engines and neither produced any fuel. I then checked and cleared the lines and fittings and everything there was ok. I ran the engines with the lines disconnected from the elbow coming out of the carb body and there was no fuel coming out there either. I removed the carbs and went through them and found nothing clogged...no bad o rings...fuel filters were crystal clear. I checked pop off pressures and both were at about 32psi. I dont understand why I dont have fuel coming out of the elbow(its clear) while the engine is running since its not going through a jet or anything inside first. I thought maybe there might be a fuel delivery problem so I ran the fuel line directly to the gas tank bypassing the fuel filter and selector valve....still no change. I have the black fuel lines...not the bad gray ones. It still runs great high speed if you can get it over that hump(hesitation). Any suggestions would be greatly appreciated!! P.S.....tested pump diaphragm and it held the 4psi no problem