I'm think you will find that there are requirments for the engines to run up to full power with fuel booster pumps off. As a flight crew the last thing you would wish for is you have a total electriacal failure and to make matters worse the engines stop.
Most aircraft in the past I ran would operate perfectly at take off power with all pumps off, normally carried out after tank entry and fuel system breakdown... this included the B737 Jurassic and classic.
