RE: Quadra 52 won't run under 3500 HELP
I missed the fact you had replaced all the diaphragms already. That make it very interesting to find out what the cause of your problem may be. Please keep me informed as to what Dick diagnoses the cause of the problem turns out to be.
I reiterate, Dick is a very professional gentleman and he will let you know exactly what's the cause of the problem is and how to better fix it. I am sure he will have the engine back to you in very short time.