1969 Mercury 7.5 - no spark

[jeddiet]

I have acquired a Mercury 7.5 outboard from an estate sale that appears to have been used very little. The problem is that it has no spark. Flywheel removal revealed an ignition system that appears immaculate. Serial is 2636xxx which indicates an early 1969 model. Points were glazed and non-conductive until filed. Still, no spark. Coils look new with no signs of swelling, cracking or corrosion. I even held the end of the spark plug wires and pulled the starter. Nothing. All associated wiring looked factory fresh. I understand that this ignition was discontinued after this model year.
I would appreciate any input anyone may have on this problem so that this old sister can be revived.
Thanks for your interest.

 

[tpenfield]

I have the same motor. My only advice is to. . .

Make sure the points are set correctly
Make sure the magnets did not fall off the flywheel
Clean all of the electrical connections
Make sure the ignition kill button is working properly

BTW- those engines have a steel drive shaft, which does not hold up well in salt water. I swapped out the drive shaft of my motor with a shaft from a 1980 model.

Mercury switched to stainless steel drive shafts in about 1979. That motor stayed pretty much the same for quite some time starting from the late 1960’s

 

[Scott Danforth]

check the kill switch

 

[jeddiet]

We have spark! Here are the causes: In no particular order, oxidized points contact surfaces (file the points and check with ohm meter), and factory paint overspray over the flywheel magnets and the coil magnetic pickup areas (3 per coil). I used sandpaper to remove the paint. Now, nice blue spark.
This motor shows evidence of very light use. It probably never did run to its full potential and now we know why, and so do you. Why the 1st owner didn't seek help to correct the issue will remain a mystery.

Now onto the fuel pump, carburetor, and water pump.

Thanks to the readers and responders. I certainly appreciate you lending your experiences. I may need your help again really soon.