We would like to find a reducer to keep a 12 V coil from buring up the points and condenser on the engine. Our goal is to be able to install a 12 V battery with a 12V coil but keep the 12V from burning up the points. We can not keep a battery in the tractor from dying and going to low charge after a very short period of use. This is causing it to stall and miss after only 45 minutes of run time.

Dave Spencer, September 2008

Presume your 8N was originally 6volt?
Have you changed the dynamo for a 12volt unit and polarised it to suit (+ve. or -ve. earth)?
Is the coil you are using truly 12v. and not a more modern 6 - 8v. coil which requires a ballast resistor.
Ford cars used a special resistor lead, while Vauxhall at one time used a resistor unit fitted to the coil itself.
Fitting a voltage dropper to a 12v. coil will reduce the spark energy causing difficult starting.
If you use a low voltage "cold start" coil you also need to fit a starter solenoid with the extra terminal which switches available battery power to the coil when cranking the engine, as the battery voltage drops.
Thus, the 6 or 8v. cold start coil will get its full share of power. When the solenoid releases the coil is fed via the ballast resistor.
The terminals of later coils are marked "+ve." and "-ve."
rather than "sw" and "cb" like the older ones. Make sure that it is connected accordingly.
Hope this may be of some use to you!

Mr. Toad, September 2008