Hi all, I have a magneto horn currently not acting like a horn. I made the adjustmets as so stated in the Service Book but to no avail.

Someone told me that the horn will not sound on Mag at idle. My mag has about 4 VAC at idel and was told that the horn needs more voltage, as in when the moter is rev'ed.

Any other thoughts, tricks and or repairs I need to make.

Thanks...

I am surprised that your car would even run on mag with only 4 volts at idle. Clearly that is a weak mag if that truley is the voltage at idle.

Hmmmm well new to all of this. I will recheck my mag voltage. What should I be seeing at idle?

Thanks

Chris
See the other thread on this forum entitled "magneto output voltage". The procedure and a diagram of how to conduct the test is shown in the messages.
Ron the Coilman

OK thanks Ron

Chris,

They will work with the engine at idle -- but they sound louder and have a higher pitch as you increase the engine RPM/voltage output.

Have you checked the wiring to and from the horn? You could put a temp horn button between the horn and the mag and see if that works. If so, then it is the wiring / horn button.

Also, have you ever heard it work? Did you double check to make sure it is a mag horn and not a battery horn? The battery horn won't work on mag power and the mag horn won't work on battery power. Did you make sure that the proper power source (Mag or battery) is going to the horn?

Hap 1915 Model T Touring cut off and made into a pickup truck and 1907 Model S Ford Runabout in SC

Hey good news... I rechecked the AC output of the mag. I have 12 VAC at idle, not 4 VAC. The 12 VAC was measured with a dirty ground so things may be better than that. In addition the horn is working. Had to adjust the screw on the plunger. Horn now rocks... well so to speak. Thanks to everyone for the input.