Points type ignition - Basic questions and understanding - Magneto

Hey all,

Just wanted some info on this. I have a 25hp with points, condensers, coils type ignition. There is no alternator and the motor is electric start.

1.) Is the term 'magneto' just a word to describe points,condensers,coils type ignition or is magneto a separate part altogether that goes along with this? If it is separate, do all motors have them?
2.) How does this motor generate its 12 volt power to energize the coils?
3.) Can this motor even be run without a battery hooked up and using the pull start?
4.) Will it generate enough power to charge my cranking battery?
5.) Can one load accessories on and still expect the motor to keep the battery charged (radio, lights, etc.)?

I am asking these questions as I am going to buy a designated cranking battery for this motor and considering weight and cost, wonder if I can get away with a small cranking battery that can be kept charged by the motor, or do I need something that will supply all power for the duration of any outing I may take.

Thanks,
~JC

Re: Points type ignition - Basic questions and understanding - Magneto

Well, if you do indeed have magneto ignition, then there will be no charging circuit. You must recharge the battery periodically depending upon use. The engine can be started by starter motor or by hand (with the key on) and will run without a battery. You can run accessories but they will drain the battery.

The magneto is a complete self energising ignition system located under the flywheel. It consists of a plate carrying two coils, two sets of points, and two condensers. As magnets in the flywheel rim pass the iron cores of the coils, they generate a magnetic field in each. When this field collapses after the magnets pass, it generates a high voltage pulse in the coil windings which is sent to the sparkplug. This is controlled (timing) by position of the magnets in the flywheel and by the points.
This is a very simplified explanation.

Re: Points type ignition - Basic questions and understanding - Magneto

Here is a magneto style engine. A pic to go along with what frank said.

Re: Points type ignition - Basic questions and understanding - Magneto

Be carefull with your terminology Magneto is not the same as coils ....Magneto uses spinning magnets under the flywheel to energise the under flywheel magneto coils.. Coil igniton used on some Chrysler has car style coils mounted externally and there are only points and condensers under the flywheel ..This system must have a battery to make it go ...

Re: Points type ignition - Basic questions and understanding - Magneto

Always include the model and serial#s so we know what were working on.
1.) Is the term 'magneto' just a word to describe points,condensers,coils type ignition or is magneto a separate part altogether that goes along with this? If it is separate, do all motors have them?
Different type of ignition system.If you have coils you don't have a magneto system.
2.) How does this motor generate its 12 volt power to energize the coils?
The stator and flywheel produce the voltage to charge the battery and run the motor.
3.) Can this motor even be run without a battery hooked up and using the pull start?
Yes
4.) Will it generate enough power to charge my cranking battery?
If the battery is not too dead it will keep it charged.
5.) Can one load accessories on and still expect the motor to keep the battery charged (radio, lights, etc.)?
Yes.

A 450CCa will be all you need to start and run any electronics.If you play the radio and leave the depthfinder on all day it might kill your battery.
Depending on the size of your boat,a small lawn tractory battery with a battery switch can be installed.Or just be safe and install two 450CCA and a switch.J