Re: Weak Spark

Tue Mar 13, 2012 10:29 am

Ok, being a magnet guy, let me help with the rumors of lost magnetism.
Permanent magnets can lose magnetism.
Over Time, some magnetism is lost (usually insignificant to the design of the device)
Heat can discharge a magnet (but it takes a lot of heat). Typical ALNICO magnets keep their magnetism up to about 1000 degrees Fahrenheight
Impact can discharge a magnet. By repeated impacts to the magnet, the material demagnetizes.
A large impact can break the magnet into pieces causing multiple poles and a much lower performance. (This is the most likely cause of a magnet related issue)

A non-broken magnet can be re-energized using a capacitive discharge magnetizer. The magnet would have to be removed from its assembly and inserted into a coil and then a large DC current would be directed through the coil. You cannot "overcharge" a magnet. The magnet just saturates with as much magnetism as it can hold.

Re: Weak Spark

Wed Apr 30, 2014 8:41 am

Closest thread I see that has bearing on my issue of the day. I'm attempting to change the points and condenser in my distributor (never done this before) and I see the pinion gear lining up with the rotor. There are three screws holding a plate over the area I gather I have to access to get to the points. Is this correct? If so, how do I get the plate over the pinion gear? I'm not pulling on the pinion gear until someone here tells me to.

Re: Weak Spark

Wed Apr 30, 2014 9:12 am

I think you got your answer in another thread, but the pinion gear just pulls off. While there inspect the teeth of the pinion gear, if they are worn down to sharp points replace it also or it will eat up the teeth of the rotor.

Re: Weak Spark

Wed Apr 30, 2014 9:15 am

John *.?-!.* cub owner wrote:I think you got your answer in another thread, but the pinion gear just pulls off. While there inspect the teeth of the pinion gear, if they are worn down to sharp points replace it also or it will eat up the teeth of the rotor.


They look good, John. I need you back in the other thread. And contrary to what some people say, things can get worse. I didn't know there were this many parts to a tractor.

Re: Weak Spark

Sat May 03, 2014 11:16 pm

Rick Spivey wrote: the points in a magneto are gapped to .013", while a distributor is gapped to .020".


I don't understand this distinction. I have a magneto coil and what I call a distributor, or at least a distributor cap. What is the difference between the two? Pics would be great.

Re: Weak Spark

Sun May 04, 2014 6:15 am

Image

Magneto, courtesy of TM Tractor. Note the square coil cover.

Image

Distributor, also courtesy of TM Tractor. Note, no coil cover, because coil is external.

Both have to have a tower to distribute the spark. Due to the internal design, and how each controls "timing" of the spark, a magneto is gapped to 0.013", and a distributor to 0.020". If you have a magneto that has been "converted" (a kind word) to run from an external coil, you still should gap the points to 0.013", because the internal mechanisms have not been changed, just the spark source.

***Edited because I had the wrong number in the last statement. Thanks to Don McCombs for the correction!***