8n with no fire

after which, amp meter was showing no movement when key was on.
my dad said that there was no fire to the plugs, which by the way were re-gapped to .028 as per manual. *.025-.028*
he's now sitting in the shop staring at the tractor trying to figure out whats wrong...
you guys have any ideas?

See if the coil is firing. Pull the center wire off of the top of the distributor. Put a piece of wire in the end of the distributor wire and hold the other end of the wire close to the engine block while someone turns the engine over with the starter. It should show a blue spark every time the points open.

Put the coil wire back in the distributor and pull out one of the spark plugs. Hook the spark plub wire to the plug and lay the plug on its side on top of the block. Crank the engine again. Does the plug produce a blue spark?

If not, then either 1) coil is bad, 2) points not working, 3) bad condenser, or 4) not getting voltage to the coil primary winding.

Use a voltmeter to see if there is voltage at the coil when the ignition switch is on.

the only thing that has not been replaced was the coil and the gennie.
How do you test the gennie to see if its working properly?

The ammeter should show a slight discharge when the points are closed (the current through the ballast resistor and coil). The fact that you don't even get a flicker when you turn the key on suggests that current is not flowing to the coil from the battery. See if you have voltage to the coil. If you don't, trace the wiring back and find out why not.

But, you can't get it to run!

Hmmm, charge the btry up real good tonight and do the tests without the genny hooked up.

How far is it to Magnolia from Katy?

I find it better to use an ampmeter insetad of a voltmeter. Regardless of whether it's a 12V or a 6V system, you should have about 4 amps (for a 4 cylinder engine with points) flowing in the coil circuit when the points are closed and the engine is hot.

so, in a 6 volts 4 cylinder system, you need about 1.5 ohms total in the coil circuit when the engine is hot. That includes the resistance in the coil primary winding and in any other type of resistors in the circuit.

In a 12V system you need about 3 ohms, total, in the coil circuit. 12V coils labelled with "External resistor not required" will have the 3 ohms in the primary winding and no external resistors are necessary.

The ballast resistors are variable resistors. When they are cool, they have less resistance. This gives more current to the coil to make the tractor easier to start. As they get hot, the resistance goes up and the coil current goes down to approximately 4 amps.

If you have a volt/amp meter, follow the user instructions on how to hook it up to get amperage readings. (put the two leads in series with the coil circuit and set it to read AMPS)

Put the ampmeter in the coil circuit and rotate the engine by hand till the points are closed. If the reading is more than about 4 amps on a 12V system (with the proper coil), or more than 6 amps on a cold 6V system, then something is wrong. You could heat the ballast resistor with a heat lamp if you wanted to and take another reading. When it is hot you would want about 4 amps.

With 6 cylinder engines with points you want 6-8 amps in the coil circuit.