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No Spark one cylinder Evinrude 7.5 HP

H

hosocat

New member
I inherited a 1981 7.5 hp Evinrude that is not running. I thought I'd see if I could get it back in action. It is sparking on one cylinder, but not the other. Not a plug problem, I switched them to make sure. Would it be reasonable to assume that one of the coils is bad?

Also, I originally thought the coils were under the flywheel (yes, I am that ignorant) so I removed the flywheel. When reinstalling the flywheel, is there a torque I should tighten the nut to?

Thanks for any advice.
 
A bad coil is a possibility. But not written in stone.

Correct flywheel nut torque is essential. But I don't know what it is on a '81. Probably 40-45 ft lbs, but wait for a better answer.
 
40-50 ft lbs for flywheel nut. Swap the coils and see if the problem follows the coil? If it stays the same the power pack is likely bad.
 
Is there any kind of maintenance I should do while I have the flywhweel off? I notice that on the inside of the flywheel, on the outer rim, there is a very slight bit of surface rust and smudging. Should I take some 1000 grit sandpaper and lightly polish it up, or would that cause damage?
 
You can clean it up with 220 grit and a wire brush just do not get anything on the upper crank seal. then just torque the flywheel down and confirm it has good spark on both cylinders. Use a open air spark gap tester it should jump a gap of at least 3/8 inch with a crisp blue snap on both plug wires.
 
Have you replaced the impeller? You want to do that before you fire it up and change the gearoil. Start it up in a barrel of water about five inches above the cavitation plate.
 
I removed what I think is the bad coil. I notice that the orange wire from the coil (not the ground wire) goes into a three pronged plug. This plug also has the orange wire from the other coil. So both coils are joined together at this three pronged plug.

Do people usually replace both coils when one of the coils goes bad? If the smart way is to replace just one coil, how do you deal with the plug? Should I just cut the orange wire before the plug and splice the orange wire from the new coil onto the cut wire from the old coil that leads into the plug? Or is there another way?

Thanks for any advice. Hope my description isn't too confusing.
 
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