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r_d
 
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Default Mercruiser Still Won't Start


"TSC" wrote in message
...
I have the Siloc book. I went through the troubleshooting, and I have no
spark anywhere.

Curiously, the wiring diagrams in the book do not show an external ballast
resistor. I have following the wires from the coil and I cannot locate one
either.

The original coil (which I replaced) says the only use it with an external
resistor. I made sure the new coil was for use with an external resistor.

Any clues as to where the resisitor would be?

Would a faulty resistor allow it to crank, but show no spark?

Note that I checked for spark at the points, by pulling the coil wire and
holding it near a ground, and by putting a spare spark plug into a plug
wire.

Trust me... there is no spark.


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