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1984 75/hp 4 cylinder Mercury spark problem

K

KenWeaver

New member
Hello all
I have a 1984 75/hp 4 cylinder Mercury. I'm get a strong spark off of #2 and #4 cylinder but no spark from #1 and #3. This what I check coils, all wiring and the trigger system all look good. I don't know how to check the switch box or the stator. Any ideas?? Thanks
Ken Weaver
 
The best way is to get a repair manual and follow the trouble shooting process in the manual. It will come in handy when replacing parts and fine tuning your motor too. You can also try cdi electronics site and key in your stator's part numbers or power pack's part numbers and search for trouble shooting. You will also need a multimeter to check the resistance and DVA adaptor to check the direct voltage at cranking on the stator and pack.
Did you measure the resistance on the coils? If you don't have the coils' spec, try this: Swap the coils from the cylinders that have spark to the ones that don't. If the ones that don't now have spark, it's the coil issue. If spark does not move then it's likely the pack or stator.
Good luck.
 
If you are loosing spark to (2 and 4) or (1 and 3 ) you need to check for loose or broken magnets under the flywheel first.

If you were loosing cylinders (1 and 2) or (3 and 4) you would have to start looking at the stator and switch boxes.
 
Hi did ever get this working after 11years :). i have the same problem and was wondering what you changed that fixed your issue. i have no spark on 1 & 2. i moved the cables from 3 to 2 and got spark on 2 and no longer on 3. what would this test suggests? stator or switch box?

i did look at my stator and the wires seems a little worn but they are reading the recommended resistance ranges as per specs.

thanks,
Hamid
 
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