|
Tractor Talk Discussion Board |
Re: JD model 40 burning points
[ View Follow Ups ] [ Post Followup ] [ Return to Tractor Talk Discussion Board ]
Posted by Rick K on August 26, 1999 at 05:51:24 from (205.181.231.254):
In Reply to: JD model 40 burning points posted by Hillory on August 25, 1999 at 21:14:05:
Burned points are very likely caused by either a bad condensor, or the wrong value condensor. A condensor actually must be matched to the coil. If you have been swapping things around a lot, you may not have the right combination any more. The condensor has a certain amount of "capacitance", expressed in microfarads. This is sometimes marked on the condensor. The coil has a certain amount of inductance, expressed in millihenries, although you will not find it marked on the coil anywhere. The idea is that they are supposed to cancel each other out and prevent an arc across the point contacts each time the contacts open. To much capacitance and the arc current will be in one direction, to little and it will be in the other direction. The burned metal on the contacts is moved with the arc. If you know what the coil you are using is actually out of, try a condensor for that engine as a starting point. You can also try running without a condensor briefly to see what side of the contacts the bruned metal is deposited on. This is now the side that indicates too little capacitance. You can use that as an indicator to tune the system. If you know anyone with an oscilloscope and who knows how to use it, he can help you tune it without as much experimentation by seeing what happens across the points when they open. That is one of the things that those fancy diagnostics things in a service station does.
Follow Ups:
Post a Followup
|
