Port Engine Shuts down various RPMs
 

I have a 35 ft Fountain with twin 2003 Mercury 525s, 154 hrs, Port Engine runs and shuts off at random RPMs. Replaced harmonic balance sensor, fuel pump sensor, have gage hooked up and showing to have 40 pounds fuel pressure, swapped fuel lines, electric black box on engine, computer.

fixx
 

check for loose wires @ the ignition switch,,also check the tethers!