How to check for a good magneto:
The #1156 bulb has two terminals. One at the very bottom and the
other is the metal case. Solder two wires about two foot long to these terminals
or go buy a socket for the bulb and connect the wires accordingly. Connect one
wire to the magneto output terminal on the hogshead and ground the wire other to
the transmission case or rear of the engine ground. Connect the leads of the
analog ac voltmeter on the 10 volt scale to the same two points as the lamp.
Start the car and run on it on battery. Watch the lamp. Is it lit and what is
the voltage reading on the ac voltmeter?
When running, with the 1156 bulb between the mag post and ground, running on
battery, it glows bright. I get 10v at idle and about 25v revving. It would
appear that running, the mag is giving off the proper voltage.
How to bypass the ignition switch to rule out a bad switch.
Get a jumper cable with clips on each end.
KEY OFF, and DISCONNECT the battery, in case there is any back feed..
Jumper from the MAG post directly to the coil box input terminal (on firewall the bottom center insulator post) thus by passing the switch.
Again, have the battery disconnected so you don't demagnatize the magneto.
How to Check for a Good Coilbox Switch
Posted by Warren Mortensen on Saturday, 16 November 2002, at 12:35 a.m., in response to Re: I don't understand it Tony??, posted by Bruce Tolson, Roanoke VA on Friday, 15 November 2002, at 10:31 p.m.
In the case of any T with the switch ON the coilbox, the instructions
won't work.
Instead, remove the front plate from the switch and, using a jumper wire with
alligator clips, jump the mag side of the switch to the wire leading to the
brass buss bar in the bottom of the coil box. Probably
best to check for the proper connections with a continuity tester or ohmeter if
one isn't sure which wire is which ( on L.H drive cars, mag is usually coming in
on the driver's side, battery on passenger side,
and wire to buss in center if I recall correctly). Since the coilbox switch is
beefier construction than the dash switch, any problems can usually be solved by
cleaning contact wipers, tightening terminal screws and looking for failing
non-conducting material and fabricating something to replace it.
If one rewires one of these boxes they should use buss wire, not multiple stranded wire which can break more easily at solder joints from the vibration and because it must be wrapped or hooked around the terminal screws securely in the switch. No room for ring lugs here in my opinion. Stranded wire will not stay securely under the screw when the screw is tightened.
How to check for a bad switch or magneto
Posted by John F. Regan on Friday, 25 October 2002, at 9:54 p.m., in response to Re: mag, posted by Dennie Kirkpatrick on Friday, 25 October 2002, at 11:45 a.m.
To eliminate the switch and wiring, do the following EXACTLY!
Disconnect the wire from the magneto post on the hogshead. Connect that exact same wire directly to 6V Positive of battery. This connection is temporary but make sure it is solid. Now start and run in the "Bat" position of your switch. Move to the "Mag" position on the switch. Drive the car and keep switching back and forth periodically and jiggle the switch key on occassion too. If you notice a difference and the car does not run the same in "Mag" position as in the "Bat" position then the trouble is in the switch or wiring. If you do not see any difference at all then your trouble is in the magneto post or internal magneto.
How to check for a bad cutout
Make sure it is a cutout and not a voltage regulator.
Have someone watch the ammeter and use a pair of pliers and touch the generator terminal and the cutout screw that the wire from the wiring loom attaches to. If the ammeter registers amperage, the cutout is bad.
How to check for a bad generator on the car
Remove the cutout. Take a multimeter and set the display for 10 volts. With the car running normal, touch the positive (red) multimeter lead to the generator terminal bolt. Touch the multimeter negative(black) lead to the generator case (grounded). You should see about 7 volts. If not, something is wrong with the generator.
How to check for a grounded 3rd brush in the generator
Take a multimeter and set to continuity. Touch one lead of the multimeter to the brush plate and the other to the brush holder. There should be no beep or light lighting (insulated). If there is the brush holder is grounded and you must replace the insulators on the brushplate.
