The early 1950's Massey Harris has been sitting a few months and needs to be moved. It is in line for a freshening up of the ignition and electrical circuit, but time has not allowed. A machine with higher priority needs repaired first so today we just do a cold start on the old Massey. At the same time we have a basic discussion about the old tractor and the upgrades electrically that its in store for.
This old tractor on occasion would fail to start with the ballast resistor in the circuit. BUT...that was always with a partially charged battery. Now a battery charged to 12 or 12.3 volts will spin the starter, but with a ballast resistor, there's not enough of a shot of voltage available to fire across the plugs with the resistor cutting the voltage to the coil. Lowering the coil input also lowers the coil output. The result is a weak or poor spark and failed ignition of the air/atomized fuel mixture entering the cylinder. A simple bypass of the resistor would usually cause it to fire up instantly. That is going to be repaired, just not now.
The second thing to change in the electrical circuit is to change the ammeter to a voltmeter. No, it's not just as simple as removing the wires from one gauge and install them on the other gauge. An ammeter must be connected in 'series' of the load, causing all the load to pass through the ammeter resulting in a movement of the needle... Now, the voltmeter needs to be installed in parallel with the applied voltage. If it is connected in series with the circuit loads, it will be come a load and divide the electricity in the circuit by half. If its a large load, the high amperage will overburden the workings of the voltmeter and render it useless. The good thing about a voltmeter is you can see the condition of the battery the instant the key is turned on. A partially charged battery will show correspondingly low voltage. THEN....when the alternator or generator becomes energized and produces output voltage back into the battery, you will instantly SEE the increased voltage on the voltmeter. No guessing if its charging or not, the answer is easily visible. To illustrate the points, if you feel like it, take a few minutes and follow through this diagram for a '72 2000 Ford :    • Delco 3 Wire Alternator Conversion Sk...  
Near the end of the video I am met with a bit of a surprise...you'll have to watch to see....I can't tell ya everything man !! LOL #coldstartmasseyharris30, #continentalF162flathead, #whyavoltmeter