8N no spark

BigDanT · Apr 16, 2011

I'm helping a neighbor with his 8n , not sure what year but pre 1951. He parked it last October and it ran fine, went to start it this week and it would'nt start. He thought it to be fuel related but I was'nt sure so I pulled a plug to check for spark... none. So begins the saga, I first checked for voltage at the coil it was showing .25 volts??? So I headed back towards the key switch, it showed fine then I came to what I am assuming to be a resistor coil of some kind it was showing 6 volts on one end and .25 on the other it also had a mud dobbers nest built in it. I'm a little better with my old 3 banger diesel, none of these finiky ignition issues to mess with. Is this how the resistor should read or should there be 6 volts on both ends of it. Also, is this tractor a positive ground? ( i hope so)
Any thoughts or ideas would be appreciated.
Thanks Dan

tommygun · Apr 16, 2011

check points gap,check voltage at points i would think you should have 6 volts at points.if tractor has a 6 volt system a resistor shouldnt be needed.dont know if pos or neg ground.

BigDanT · Apr 17, 2011

Tommygun...according to the parts book the part in question is the ignition coil resistor assembly, don't know what it does or how it works but, i'm not sure if I want to do away with it. As far as having 6 volts at the points, I am not getting power to the coil yet so I don't think I'll have any to the points either.
Thanks

simonmeridew · Apr 18, 2011

do you have voltage at the voltage regulator, located under the right side of the "dashboard"?
check to make sure you have a good ground. Yes positive ground. You can check ground polarity at the battery terminals. The usual: look for (pos) letters and/or a (+) sign near a battery terminal. In general, wiring issues are not complicated in the N tractors unless someone has tried a "work around".
simonmeridew

BigDanT · Apr 18, 2011

Did not check the regulator yet but, like I said I did have 6 volts to the front side of the resistor. I did some research and found out how this thing was supposed to work, the resistor should reduce the votage down to 3.5 to 4 volts going to the coil with the points closed will be 6 volts with points open. We only have .25 coming out of the resistor and .25 at the coil, I might be wrong but it seems to me it's time to change the resistor. I also heard of guys wiring around the resistor and the tractor running fine but I also heard that will shorten the life of the coil...Resistor on order

Soundguy · Apr 19, 2011

it will shorten coil and points life on a front mount.

check connections, switch and resistor.

soundguy

BigDanT · Apr 19, 2011

Checked the switch, had continuity thru the switch and 6 volts coming out going to resistor. Removed all wires and gave the terminals and wire ends a good cleaning, still only have .25 volts going to coil. New resistor should be in by this weekend will let you know what happens then.