I have a 1926 which I'm trying to start and I can only get spark to one plug. I can get all 4 coils sparking with lid off coil box and testing with test light - all four coils are working. However, I can only get my test light to light up on one of the connections on the outside of coil box.
Thanks in advance for your help,
Just been thru this issue with four perfect coils and car would only run on two cylinders. Spark was barely visible one outside connection of coil box. I switched coils and same thing---very weak spark. I rebuilt coil-box with John Reagan's kit and that fixed it. His kit is great, well made, and a snap to install!!! THANKS John
Coil-box was made with plywood bottom and back which degrades over time and probably has gotten wet. This shorts out spark and sometimes you can see the carbon tracking. New plywood would work as well, so have a look at that.
Probably the coil box. If you want to use your old coil box and the wood is still good change out ALL of the screws used in the box. The seem to loose their conductivity no matter how much you clean them. Put in some new ones and it will make a BIG difference in how your T runs.
Or you can buy a rebuild kit from John Regan and be done with it.