2008 150 four stroke charging question

[berthelot0405]

I have a 2008 four stroke and was wondering with the engine running and i disconnect it from the battery can the charging system keep the engine running.. I had an issue this weekend where i had a battery go bad, and swapped it to another battery to get it started but when i disconnected it the motor killed. just wondering if this is normal or should i check the charging system out.

[boscoe99]

Generally, no, the charging system will not enable the motor to run with the battery disconnected.

Maybe the motor will continue to run at an idle without a battery installed but it might not run so well. First time you use the trim button it will die.

The motor was designed to have a battery installed when the motor is running.

The charging system is pretty simple to check. A fully charged battery will indicate approximately 12.7 volts. Start the motor and when it is warmed up take it to a fast idle. Maybe 1500 RPM's or so. Check the voltage at the battery. You will generally see about 14.5 volts or so. This indicates the generator is working as it should and providing current to the battery.

[99yam40]

Something to think about,

some motors will fry the regulator due to bad connections a battery
So it is a very bad idea to disconnect battery while motors are running

[rodbolt17]

a very VERY bad idea.