Bought to revive. supposed reputable mech. $1650 & 8 weeks later will run like scalded dog from quarter throttle up. Will not idle. to get it to quarter throttle have to feather choke button. Crank case vaccum @ idle almost none excistent, plenty above quarter throttle. Help. Mech is lost. He's tried new carbs, broke block down put new gaskets, electric fuel pump. He's lost