Would 2019 Yamaha shutdown when disconnected from starting battery when running?

[Yamaha18]

Would 2019 Yamaha 70 hp (F70) shutdown (stopped running) when disconnected from starting battery when running?
i wanted switch to a less charged battery (spare) after i started F70 outboard using the main battery. But, the running motor stopped? This would not happen for older outboard (my 1982 Johnson 90). Is this right? I didn’t think my F70 should stopped running when disconnected from battery.
Thanks for your help!

[99yam40]

bad connections on a battery can and will fry the RR.
even on newer cars/ trucks it is a no no to do that
electric fuel pumps, injectors, and ignition running off of the 12 volts , it sounds like a bad idea to disconnect a battery

[robert graham]

Maybe just turn motor off, switch batteries and restart the motor?

[DennisG01]

Connect the drained battery to the engine. Use jumper cables from the good battery to the drained battery.

[99yam40]

I am thinking charging the drained battery and then testing it before hooking it up to a motor I the best thing to do.
new motor, so do not do something that might hurt it

[rejesterd]

You can pull-start it in an emergency, but it won't run if you disconnect the battery. It protects the rectifier/regulator. If you want the running engine to charge the weak battery, then do what Dennis said. However, the owner's manual warns that a battery below 9V won't allow the electric fuel pump to run. So it can't be too weak if you do it.

[boscoe99]

Would 2019 Yamaha 70 hp (F70) shutdown (stopped running) when disconnected from starting battery when running?
i wanted switch to a less charged battery (spare) after i started F70 outboard using the main battery. But, the running motor stopped? This would not happen for older outboard (my 1982 Johnson 90). Is this right? I didn’t think my F70 should stopped running when disconnected from battery.
Thanks for your help!

Your F70 uses a completely different ignition system than your 1982 Johnson 90 HP used. The F70 uses a battery to power the ignition system. Just like your automobile does. Your Johnson uses a magneto under the flywheel for its ignition system. Just like a push lawn mower uses.

Disconnect the battery and it will do just what you saw. Stop running.

If you have two batteries, one charged and one dead, use the charged battery to start the motor. Once the motor is up and running simply connect the good battery to the dead battery. The dead battery will now be charged by the motor.

[99yam40]

Boscoe is alive and kicking,
I thought you may have followed Rodbolt somewhere

[boscoe99]

Nope. Still around. How's you?

[99yam40]

I am hanging in there and doing well .
thought you headed south for a vacation again.

probably not enough going on here to keep you interested

[Yamaha18]

Thank you for elaborating the difference. Amazing new technology. Kudos to outboard engineers.
I like the car illustration. I will invest in a new battery to rid the problem once and for all. No time to mess around the petty things, so more time to go enjoy boating and fishing.

Your F70 uses a completely different ignition system than your 1982 Johnson 90 HP used. The F70 uses a battery to power the ignition system. Just like your automobile does. Your Johnson uses a magneto under the flywheel for its ignition system. Just like a push lawn mower uses.

Disconnect the battery and it will do just what you saw. Stop running.

If you have two batteries, one charged and one dead, use the charged battery to start the motor. Once the motor is up and running simply connect the good battery to the dead battery. The dead battery will now be charged by the motor.