In Reply to: 9N Spark/No Spark posted by John Parker on January 20, 2019 at 12:05:50:
At 6.24V a 6 volt battery is only 80% charged. Add any resistance anywhere else and there may not be enough voltage to make sparks.
By coincidence my 6V 8N suddenly dropped dead while grading a low spot in the drive yesterday. It was running fine but I did have it idled down to move as slow as possible. Suddenly it just quit. No sputter or anything, just dead. Checked gas, ok. Checked spark, nothing. Hiked back to the shop and got my meter. Measured 6.24V at battery, key switch, and at coil. Still No spark. Last time this tractor failed to start it turned out to be some sort of deposit on the points. Hiked back to the shop to get a small file and burnisher tool. Aggressively filed the points, polished them with the burnisher, then reset the gap. Tractor fired right up. Set revs higher so it would bring the battery back to full charge. Ran it for close to an hour with no trouble. It is past time to go thru the electrical system on this tractor and shine all the connections, especially with all the rain and damp we have had for the last few months. Dampness just accelerates corrosion on everything.