Keith

Just posting info in case anyone is searching the board for a similar issue.

Symptom: New engines with electric fuel pumps installed over winter. Boat would run for variable times up to 45 minutes under load, then 1 engine would shut down and would not restart, happened 3 weekends in a row while out on the water testing other adjustments we had made to the engines (non-electrical stuff).

Found no spark at coil. Tested the coil itself (once it was removed) and found no continuity which indicated bad/burned out coil. Fried 3 coils in 3 weekends before figuring this out.

Voltage at battery was 12.45 volts but voltage at coil with ignition switch on was 10.75. Tracing what was connected to the coil, mechanic had installed new Holley Blue Marine fuel pumps to ignition coil. Theory was the fuel pumps were robbing voltage from the coil and burning them out. Rewired the fuel pumps directly to the battery (with an inline switch to test the theory). Voltage at the coil was now 11.9 volts. Boat ran for nearly 4 hours with no problem.

The other engine never burned up a coil, voltage on that coil was at 11.25 but we're re-wiring both now directly to full 12v source with a relay system, no other accessories will be on that source to ensure full voltage to both.