My 1915 Touring, starts well on the magnet. But jerks and misfires when I light bulbs, where do I start looking? Assembled new 8W bulbs.
I have dual magnet windings, original 1915.
Grateful for advice.
I forgot to write, I have no alternator and starter.
There are a couple people on this site that know this area better than I, but I will start asking for clarification.
What is the "voltage rating" (or requirement) for the bulbs you have? Are they wired in series (like a '15 Ford was originally), or wired in parallel (like almost everything since 1920)?
It sounds as if the lamps are pulling the voltage down. If the wrong kind of bulbs are used, they could act as a "high resistance short" which could pull the voltage down enough, especially if your magneto is slightly weak.
For the proper 1915 wiring, the bulbs must be "two pin" and "single filament". If, for instance, they are "two pin", but "double filament", they will take your power through the filament to ground (not the other bulb). Or you could have "single pin" with "single filament", similar results. And the bulbs would not be operating at the proper voltage ( two 12volt bulbs in series operate at 24volts, while two 12volt bulbs in parallel operate at 12volts). Are both lamps lighting up equally?
Can you measure the voltage output for your magneto? You cannot use most digital volt meters for a T. You must use a good analog meter. It is also best to use a load (a light bulb will do) for the measurement to be accurate. Also, remember to measure the voltage AC, not DC.
I love your '15! And that is a great photo, by the way.
Drive carefully, and enjoy, W2
Check your lighting wires to see if there is any bare wire showing and possibly causing a short circuit to the car body Ake. Do the lights come on at all?
If you don't find a problem there, then you should check the magneto with an old meter to see how much voltage is there. Maybe there isn't enough voltage to run the coils and the lights.
Another option is to add a 12 volt battery under the rear seat and wire rear and headlights to operate off this battery (use 12V bulbs). Most batteries will operate lights for several hours with no problem. Unless you do a lot of night driving, this will work recharging the battery back at the garage.
If you are a purist, ignore what I just posted and spend some money to rework the magneto system. It should work with the correct bullbs wired in series as pointed out on previous posts.
Willie gives me an idea, wire a 12 volt battery to run the coils and then see what happens when you try to run the lights with the mag.
I'm betting the lights will not work very well.
They take a lot more current than the coils.