no spark at coil but i have voltage

[marty2]

Can't start my 3.0 mercuiser alpha drive

no spark at plugs and weak spark from coil,
even with a new coil i got no spark.
i ran a few voltage tests and found
that the voltage dropped from 12 to 5 when the starter moter was running; could the starter moter be drawing to much volt?
if so, why would it all of a sudden start to drain to much?

 

[Bondo]

Re: no spark at coil but i have voltage

Ayuh,... What igntion do you have,..?? Points,..??

 

[marty2]

Re: no spark at coil but i have voltage

i have a standard pionts/condensor ignition

 

[ABackman]

Re: no spark at coil but i have voltage

Unfortunately I am having a similar issue with my Thunderbolt IV ignition system. Same symptoms just with digital ignition. I've replaced the module, coil, ignition sensor (which you have points instead), and cap & rotor. I have 12 volts at coil but extremely weak. If or when you solve the problem can you please follow up. Maybe, by some slim chance, the two fixes will be related. Thanks and good luck

 

[maxxman04]

Re: no spark at coil but i have voltage

marty2, have you checked the ballast resistor? also, check ALL connections and grounds. clean off any corrosion, repair worn or broken connections not only on coil, but all. start assist solenoid, grounds, battery. make sure battery itself is good as well.