Ok first the set up. My 2r touring that my Dad gave me in 1991 has a distubtor, because he took out the mag back in 85. My 24 roadster the current project has it's mag. I think it works because after it starts I switch it over and it still runs. To my ear it seems to run the same no increase in rpm. Remembering Bach to my high days when the touring still had its mag it seemed when you fliped the switch a increase of rpms was the norm. I still need to shorten up the wire to the mag post so I'm thinking at that time to test the mag. Could there be a "short" in the switch that gives the coil box battery voltage in both positions?
Never heard of this if the mag in good working order you getting hotter spark
Coils may need a tune up. That is a classic sign.
When I switch from battery to mag on our 1915 Runabout. I can hear a noticeable change in sound from the coils. It has recharged magnets on the flywheel. I don't notice a change in RPM though.
I'll be interested to how shortening the wire to the mag affects the RPM. You might have to adjust the timing since the voltage will be there sooner...it having traveled a shorter and maybe straighter path and all. Just kidding!!!
Vern, the wire is new and the maker of it left too much before trimming it to length. It's just too long. It has no effect on how the car runs, I will shorten it when I test the mag. The amount of increases of rpms may not be much but you can hear it pick up in rpms.
Did you clean the mag post contact?
Have you done a magneto output test?
Maybe the magnets are weak and an in-car recharge would help.
It all depends on where you have the spark lever. If it is all the way retarded, it will run worse or stall when you switch to mag. If the lever is about half way down you will either notice it speed up or not depending on the position of the lever. Here is why. When you advance the spark on battery, each notch you move the lever will advance the spark just a bit. When you are on magneto, and you advance the spark, you will notice that you move a few notches and all of a sudden the engine speeds up. Then move a few more and no difference then one more notch, and the engine speeds up. This is because the timer and the magneto work together to advance the spark when running on magneto, but when on battery, the advance is only through the timer.
You will also notice that when you speed up the engine, the magneto will automatically slightly advance the spark thereby giving you a bit more power, but when on battery, it won't advance until you move the lever.
Anyway, what I have posted give the practical application of much more technical details.
Something else I have encountered is that on some cars someone has previously connected both sides of the switch to battery and either disconnected or removed the magneto, so the only way to be sure the magneto is working would be to trace the wiring. By the way, never connect the battery directly to the magneto or wire the switch in such a way to accidently connect it or you will kill the magneto.