The Stovebolt Site Forums The Shop Area The Electrical Bay Overheating Coil

Just starting to learn about the electrical side of things and though the vast knowledge here would help. My stove was idling well for about 20 min then suddenly ran rough for a minute and stalled. After sitting for 6 hours the coil was still almost too hot to touch. It has been converted to 12v but I don't know if the coil was changed. It doesn't any indication of voltage on the coil. What I do know, it has a new 12v battery and has an old ballast resistor. The starter was changed and the coil was wired back to the R screw which just grounded it and caused the ballast resistor to get hot. Not sure if it is bad or if the coil is bad or not the correct voltage. I bough a new 12v coil but haven't installed it yet. Any thoughts would be greatly appreciated. Thanks.

A couple of things jump out here. The "R" lug on the starter is the start circuit for the engine. It provides full battery voltage to the coil for starting only. The ballast resistor voltage should come from the run circuit of you ignition switch. These two circuits come together at the '+' side of your coil. The resistors job is to drop the battery voltage to around 9 volts or so for the coil when the engine is running. Both the coil and ballast do get hot. Resistors fail in the open position so it's not bad.
Don't know if you 'cooked' your coil. If not and want things to calm things down a bit then change the value of the ballast resistor. They make them with different values. A larger resistance value resistor will limit the amount of current the coil sees. Use an ohm meter to determine the present value of the resistor if it's not printed on the side. Note: heat sinking the resistor is not a bad idea.
Also, the ballast resistor feed side (other end from coil) does not go to "R" and "R" is not a ground. "R" should be hot only in the start position of the ignition switch and the car in park or neutral, if an automatic.

beltfed, thanks for the info, it helps me understand the ignition system better. I explored it further today to check the voltage throughout and am still perplexed. I am going to pose another question in a different post. If you catch it, it would be great if you had further input. Thanks again.