1978 Bayliner Electrical System

by Jim
(Sheridan, Or)

I have this bayliner mentioned above. After running hard for 20 or so minutes (full throttle), all and I mean ALL electrical system shuts off, radio, radar, gps, lighting, engine, ignition, regardless which position the battery switch is in (1,2 or ALL). Then all power is restored, sometimes in a few seconds and sometimes in as much as 2 minutes.

Anyone encounter such a problem? The boat has 350 Chevy engine in it.