I realize that my naiveté is going to show here, but the boat is on the
trailer, and is NOT connected to the truck. I should still have a
sufficient ground though... no?



The battery you are using to crank and start the boat is in the boat right?
If so then it does not matter where the boat is as it is a complete circuit.
If you can crank it then you do have power to the system.



The voltmeter is just fine. I actually use a $4 digital meter from Harbor
Freight when I work on something. Actually, have one in each car and boat
in case of break down.



You have two primary problems.



1. No power to the coil



2. No start once you plugged the coil into the battery.



First-- With the distributor cap off crank the engine a revolution or two.
Does the rotor turn? Is there a rotor installed under the cap (yes I have
done this.)?



1. You are going to have to trace the wires from the positive side of the
coil back to where they go. I suspect one leg will go to the alternator and
one to the starter solenoid. But you need to find where each of these leads
go. Once you figure out where they go with key on test each beginning point
to see if you have 12v being supplied to the wire lead. Find a good spot on
the block and use this for all of your power tests. Be sure to also test it
to the positive side of the battery to make sure it is a good ground. The
idea of tracing the wires from the coil to their point of origin is to make
sure there are no fuses or circuit breakers that are in the system that have
blown or corroded connections that are blocking power. If you do find that
you do not have 12 volt in one of those supply locations then that will have
to be explored. Be advised that you may not have 12v coming from the
alternator as this may be powered only when the alt is actually turning but
you should be seeing 12v on the start circuit. When you have it running you
will have to replace all of the electrical tape that you will remove.



2. Remove the points negative (ground) wire from the coil. With the points
sitting on a flat lobe of the cam (points closed) put your meter into ohms
and test the resistance from the points wire (removed from the coil) to the
plate the points are sitting on (the points ground the coil to the base
plate in the distributor. You are tying to see if the points are really
supplying a ground, what resistance do you get? With this setup in place
have someone crank the engine you should now see the reading on the meter
flip as the circuit closes and opens (both of these can be done with a test
light if you have one). Next test the resistance from the plate that holds
the points to a good place on the engine block, should see a reading of
zero. Next test from the engine block to the negative side of the battery,
should see a reading of zero. If you see a see a reading of 1 on the meter,
this means the circuit is open.



Check the resistance of your coil ignition wire (wire from coil to cap
center) what do you get (your are trying to see if the wire is bad)?



Unfortunately, at this point you are on your own. Just make sure you are
seeing a real ground through the points and try to determine where in the
system the power to the coil has stopped. I really do not know what to tell
you. Hooking the coil directly to the battery should have worked. Because
it did not tells you, you have a problem with the points. They are not
pulsing the coil. And no power to the coil key on tells you there is a
power problem.



I would not get discouraged. Just systematically work you way though the
system. With the closed circuit you will see a reading of zero or close to
zero in ohms. If you see a reading of 1 then the circuit is open.



good luck,

mark