Fuel System 337F

[Jeff A]

I have a factory reman in the rear (100 hrs) and original engine in the front (1,600 hrs). With the engines not running, mixtures pulled and the auxillary pumps on, both engines are leaking fuel through the manifold drains. With the engines running with only the mechanical pumps, both engines quit normally as the mixtures are pulled. Any suggestions as to why fuel is getting to the engine when aux pumps are on and mixture is pulled?