Mercruiser 2.5 loss of spark

[Scott Farley]

Today, I lost spark in my '82 mcm120. The voltage reading across the coil is about 7volts, 12 while cranking. The coil on there is a universal coil that reads "must have an external resistor". Is this the right type of coil? Also, my boat has an aftermarket ignition made by pertronixs. It is marked o3y-v4. Is there any way to test it? Thanks in advance.

1982 Mercruiser mcm120
Imperial v182
Alpha 1 outdrive (retrofitted)

 

[Scott Farley]

Re: Mercruiser 2.5 loss of spark

Update: I bought an MSD blaster 2 coil and it fired right up!

 

[generator12]

Re: Mercruiser 2.5 loss of spark

Careful Scot.

Make sure the Pertronix is wired to a full voltage source and not to the top of the coil with a resistance wire. It may work for a while, but it's likely to shut down from time to time erratically. That unit needs the whole 12 volts to it (red wire). If you're using the resistance wire to the coil and the pertronix is connected to it, you're probably going to see the no spark situation again.

Voice of exprerience here.