Flywheel magnet keeps rusting?

donens2018 said:

I agree with posters on rust not affecting the ability magnetic field. However, lets review what rust is. It's the break down of steel/iron due moisture/water. This is why when the rust is cleaned away, the parts shows as pitted. The breakdown is composed of fine particles of decomposing steel/iron, which does affect the engines ability to start or make a spark. The accumulation of rust/fine particles can easily be enough, reducing the air gap to the point grounding out the coil, just like the ground wire would. It seems odd to me that many engine manufacturers have modified flywheels so the magnet portion is raised, in some cases quite a lot (Kohler CH Series). Just my two cents and 40+ years repairing!

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Remember way back in high school when they tried to teach you the fundamential principles that described the behaviour of everything in the universe, people including.
All bodies will try to revert to their lowest energy state, they are not degrading, deteriorating or doing anything other than reverting to the energy level where they are in equlibrium with their surrounding
Thus steel which was made from rust which is it's natural state in the enviroment will give up the energy used to raise its energy level from rut to steel and revert to rust it's natural state.
And the same goes for every metal, every piece of wood and even plastic.
The only real difference is the rate of the reversion and that largely depends upon the strength of the oxide, sulphide, chloride, hydroxide, iodide etc etc that forms on the surface

I have read a lot on rust and spark strength and wanted to put the rust idea to rest as some believe it has no affect. I also thought it has no affect. My engine had no spark after sitting in the shed for 5 years. I changed plug then purchased a new stator still no spark. Measured AC output with my multi meter while pulling over. It read 9 volts AC stator output. I reluctantly cleaned the magnets redid test. To my surprised I now got 12 Volts AC output from stator after cleaning and a good spark. This puts this matter to rest.... rust does affect magnet strength which affect magnetic fields thus low AC output. Since all the electronics operate on a min voltage and if that voltage is not reached it doesn't operate. If rust can affect spark strength so can paint. I have read on here to paint the magnets to prevent rust. After this test i would not do that. Paint like rust is another lawyer the magnetic field needs to go through which can affect spark energy.

If I started with magnet cleaning I could have saved some $$. Just couldn't believe it makes a difference....

Sorry your wrong. First, magnetic flux is not affected by rust. Second, you don’t understand that the charging system and the ignition system have NOTHING to do with each other on today’s small engines. They are totally different than your car, and totally separated. A basic understanding of the workings of small engine systems would tell you that. Have no idea of what solved your problem, but it wasn’t what you described.

Rust was not the problem unless it was very thick and creating a bridge.
In most cases where people think that derusting has made a difference have been mislead by the fact that most plugs since the 50's have been self cleaning so the simple act of unpluging & repluging the wire cleans the contact faces, lowers the resistance & thus increases the voltage read.
Rust does not affect the magnet flux produced by a magnet, never has never will.
IF you have trouble believing it then sit down with a good book on ferro-magnetism

As said, a little rust will not stop the magnet from working but if u want to rustproof that and your ignition module, use linseed oil. Motor oil will fairly quickly dry up and it will rust in only a few months. I use linseed on alot of outdoor stuff like my metal wagons. After 3 years being stored outside so far, still no rust.