Engine ran very well last season and the beginning of this then starved for fuel. New primary low pressure pump and new high pressure pump. Found that voltage at Primary went from 12 Vt at pump to 0 in a few seconds and high pressure went from 6 vt to 0 in same time. tried Circuit breakers and found not tripped. Any thoughts about what might be going on, all other electrical on engine and boat works. I do not want to start tearing things down without good idea of what may be happening. Any help would be appreciated