What would short out ignition power after the switch?

[Ozshadow]

My boat would not turn over when I went to start it the first time this year. I have power to the B terminal at the switch. I get power in the accessory tab.

When I test the ignition wire when the switch is in the run position the voltage tanks on both the ignition and the battery side like it is shorting to ground, under 1 volt. Gauges do not work. Blower and trim tabs all work. Helm breakers all have 12v power including both sides of the ignition breaker when switch is off.

Red switch is up. I’ve jiggled the shifter. The 50 amp breaker is not popped and has no power on either lug.

Battery connections are all clean and tight and easily power the outdrive lift rams.

Thoughts? It is a 4 lug plastic switch, new last year.

 

[Ozshadow]

It was plugged in. Gonna leave it charging a while and hope for the best. Maybe the batteries were drained more than I realize.

 

[Ozshadow]

Still nothing - when the switch is turned to run, voltage drops to something like 0.18v. Turn it back off and it takes about 10 seconds to watch the voltage rise back up to 12+v at the switch breaker and switch B.

 

[scoflaw]

Check for voltage on the heavy r/y wire that goes from the 90 amp fuse on the starter to that 50 amp breaker.

 

[Ozshadow]

SOLVED - main battery cable loosened at the starter solenoid. Had backed off about 1/8" or so. Surprised I did not have problems last year but also happy I caught it before it became a huge explosion or left us being towed in.