Another small engine question (OT Not Valkyrie)

[vanagon40]

I just replaced the coil on an old Lawnboy 2 stroke push mower.  The mower now runs great.

My question is that it would appear that the only electrical part is the coil.  I know on my old 4 cycle mowers, I had points and a condenser under the flywheel.  I assume I do not have those on my 2 stroke Lawnboy (if I do, I do not see where they would serve any function).  What happened to those parts?

I did try to google the answer with no success.

[R J]

If you pull the flywheel, you will see the pickup places on the inside of the flywheel.

If they get rusted too bad they will not run.    Ya have to pull the flywheel and sand them down.

All your little goodies are under that flywheel.

[Robert]

On modern 4 stroke engines points gave way to electronic ignition. No more distributor, no plug wires, no individual coils replaced by a crankshaft pickup and sometimes a camshaft pickup with individual coils on the plugs and computer. Ignitions just need to switch the coil on and off at predetermined times thats all that the points did open and close according to how they ride on a cam on the crank. Below is a link that explains simple ignition systems that are on modern day lawn mowers and such. Most points are just replaced by magnets that pulse the coil when a spark is needed. A simple pulsed generator is what does this and replaced the points. No battery is required since the magnets generate their own power. But with a battery powered ignition you will still have points. Some early equipment could not generate enough power to pulse the coil so they had a small generator in them that served as power so you needed points. It did not matter that you had no battery just enough power was generated to pulse the coil through the points. But now with the magnets supplying enough power and placed around the outer edges of the flywheel they were able to do away with the job of the points by generating a pulse of current rather than open and closing points that already had power to them. A bit of a disadvantage is they pulse every time the flywheel comes around instead of the exact one time needed for fuel burn. This is why the coil has a magnet through it and is very close to the flywheel. One unit does the job less magnets, less wiring, smaller flywheels, less components all around and more reliable. Actually better spark also since you do not generate power and then have points that get dirty and drop the voltage to the coil. Basically a magneto system is what this is.  With out this we would not have the multitude of modern reliable small gas engines we have today.

This link explains simple ignition systems.
http://outdoorpowerinfo.com/repairs/flywheel_about.asp

[Momz]

On modern 4 stroke engines points gave way to electronic ignition. No more distributor, no plug wires, no individual coils replaced by a crankshaft pickup and sometimes a camshaft pickup with individual coils on the plugs and computer. Ignitions just need to switch the coil on and off at predetermined times thats all that the points did open and close according to how they ride on a cam on the crank. Below is a link that explains simple ignition systems that are on modern day lawn mowers and such. Most points are just replaced by magnets that pulse the coil when a spark is needed. A simple pulsed generator is what does this and replaced the points. No battery is required since the magnets generate their own power. But with a battery powered ignition you will still have points. Some early equipment could not generate enough power to pulse the coil so they had a small generator in them that served as power so you needed points. It did not matter that you had no battery just enough power was generated to pulse the coil through the points. But now with the magnets supplying enough power and placed around the outer edges of the flywheel they were able to do away with the job of the points by generating a pulse of current rather than open and closing points that already had power to them. A bit of a disadvantage is they pulse every time the flywheel comes around instead of the exact one time needed for fuel burn. This is why the coil has a magnet through it and is very close to the flywheel. One unit does the job less magnets, less wiring, smaller flywheels, less components all around and more reliable. Actually better spark also since you do not generate power and then have points that get dirty and drop the voltage to the coil. Basically a magneto system is what this is.  With out this we would not have the multitude of modern reliable small gas engines we have today.

This link explains simple ignition systems.
http://outdoorpowerinfo.com/repairs/flywheel_about.asp

No plug wires?  
My new Honda mower must have an antique motor (back to the future)  

[Jess Tolbirt]

the lawn mowers are like the magneato's they dont have points anymore

[vanagon40]

Thanks for the responses.