Question
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Followup To
Question -
Mr Kirkland,
I am trying to help a friend with a problem on a
Craftsman 2004 or 03 lawn tractor with an 18.5 B&S
He has replaced the magneto 3 times. Each time the problem seems solved but after about five hours of use, the tractor stops running again and will not start until the magneto is replaced again.
Any suggestions will be appreciated.
Thanks, GCL
Answer -
Hiya Gary
Has anyone replaced the primary wire supplying voltage to the magneto? Some engines use what they call a ballast resistor thats built into its supply wire. This reduces voltage to the coils. See if you can find this out for me- and I will check to see if this model engine uses a ballast resistor.
Allen,
Thanks for the info on the ballast resistor.
My friend who is working on the magneto problem will be trying to discover the origin of the problem again this week end. We will check for the resistor. I can see exactly how that would work and possibly cause the problem.
Gary Lee
Answermportant Information about Ignition Coils -
Typical Ignition CoilTypical Ballast Resistor (Voltage Reducer)Some ignition coils require an external ballast resistor (off any 1972-85 Chrysler, Dodge or Plymouth vehicle) or a full-length resistance ignition wire (off any 1958-74 GM vehicle) to prevent from putting too much voltage through the primary circuit and ignition points, which could burn them up. A ballast resistor or resistance wire is basically a voltage reducer that reduces 12 volts down to anywhere between 6-9 volts, depending on the load. If a coil reads "12 VOLTS" on its casing, then it has a built-in resistor. A resistor may not be needed with many new coils because most of them nowadays have a built-in resistor. And using a resistor doesn't effect the voltage output of a coil. It only prevents from burning it up, and it saves wear on the ignition points. The reason manufacturers don't install a resistor inside some high-performance coils is because these coils draw more amps from the battery. This causes the resistor to operate at a higher temperature, which could overheat and damage the windings within. If you prefer to use a high-performance coil, when you purchase one, be sure to ask the salesperson if it has a built-in resistor or if it requires an external one. This is very important. Jes a little blurb for my friends :)
