Re: Mercruiser Still Won't Start

I do NOT see 12 volts on the positive side of the coil with the key on. This
is using a volt meter. I tested the volt meter at the battery and got the
full 12 volts. Testing at the coil gives me nothing.

Hooking up a wire with gator clips to the positive side of the battery to
the positive side of the coil produces no change. Keeps turning over nice
and strong, but no firing whatsoever.

By the way, I *did* remove the tach wire while conducting all tests.

I changed back to my original coil and performed the tests again. No change.

I am going to have to wait for daylight to continue this saga.








Ok let me ask you this... Key on do you see 12v on the positive (+)
terminal of the coil with the key on?

If NO
then hooking up a wire with gator clips from the positive (+) battery
terminal to the positive (+) side of the coil. See if it will start if so
pull the clip off if it dies then you have a problem with the external
resistor. In this case just ignore it, go get a internal resistor coil
and run a wire directly from the ignition switch to the coil. Don't use
the external resistor coil on 12 volts it will overheat. You can in the
future use this new 12volt wire to run the electronic pickup that you will
eventually install in place of the points...... I suspect this is not
your problem as it will not start even when the starter is running.

If YES
there is power to coil with key on then I would unhook everything from
the negative (-) terminal of the coil except for the points (should be a
single wire running from points/condenser to coil). See if it starts and
runs. If so tach is dead or short in shift interrupt system. The way the
coil works is such... the coil charges when positive power is on and the
coil is grounding though the points. When the lobe in the distributor
gets to the proper position it opens the points breaking the ground to the
coil and the power stops flowing in the secondary circuit in the coil.
When this happens it creates a magnetic pulse in the coil that is picked
up by the primary circuit and is send out of the coil as a high voltage
"jolt" that is then sent to the plugs. If the ground circuit is always
grounded no spark or if the circuit does not close (no ground) no spark.
I bet this is where your problem is in the system.

During cranking the starting system will feed a full 12volts to the coil
then when the starter is off it feeds ~10volts to the coil through the
resistor circuit (voltage will depend on the resistor but should be
between 7-10volts).

From what I have read in your posts I bet you have a ground issue.

I went though something similar last year with my OMC.

Let us know how you make out.

good luck,
mark



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