2000 70 HP Johnson Outboard Wont Start

[Kmahan]

I have a 2000 Johnson 70 hp that wont start. I turn the battery on, the ignition beeps and all instruments work. When I turn the key, it kills all the power to the boat and nothing works. I have to turn the battery off then on again to get power back to the console. It is a new fully charged Battery and I have even tried it while being jumped to the truck. I thought the ignition may have had a short so I replaced it. No change. I can jump power from the solenoid to the starter and have power if I do not turn the key all the way. I f I try starting it with the key, all power is cut to the motor until I turn the battery off then on again. Any suggestions? Thank you in advance!

 

[joereeves]

Although I retired back in 1991, it's unlikely that the starter circuit and power/voltage to the ignition switch has changed and my mind locks onto a voltage drop caused by a tight but dirty main voltage circuit. And if this is so, even though a known good battery exists and is fully charged... the 12 volts reaching the ignition switch and starter circuit would be similar to trying to start the engine with eight (8) flashlight batteries... 12 volts for sure but you know what would happen as soon as you turned that key is certain.

The cure, if this is the case, is to disconnect all the cables associated with the starter circuit, battery terminals, battery switch, starter solenoid, electric starter, the main ground cable at the powerhead... clean the cable terminal ends and the components they attach to, then tighten them securely with a wrench or pliers if wing nuts are encountered.

Hopefully that cures your problem. Let us know what you find.