1984 40hp Evinrude, shut down suddenly, now no spark

js5278

Cadet
Joined
Mar 20, 2003
Messages
24
The motor was running fine. While cruising along at about 80% throttle it suddenly dropped the RPMS by at least 50%. I throttled back and it ran OK for maybe 10 seconds until I tried throttling back up. It sputtered a bit and shut down completely and would not start. Got in on my spare. Back in the garage there was no spark on either cylinder. I've never had an issue with the motor. I'm considering buying a new power pack, given that neither cylinder has spark. Is this a reasonable bet?
 

kbait

Commander
Joined
Nov 13, 2007
Messages
2,446
Most likely the cd box (power pack), but you may want to test the 2 coils under the flywheel..charge coil and sensor coil (trigger). You will lose all spark if either is bad. You can check resistance at the plug at the end of the wire bundle coming from armature plate beneath flywheel. Google CDI troubleshooting to find the ohm values/procedure. If they test good, then it's your power pack, assuming both drive coils (external) didn't fail at the same time..unlikely.

Good luck!
 

juno pierrat

Petty Officer 1st Class
Joined
Dec 14, 2013
Messages
355
for checking charge coil and sensor coil

Ohms volts cranking volt running
sensor coil 40 +/- 10 1.5 6
charge coil 575 +/- 25 230 250

this comes form 87' 48spl service manual, but parts numbers are the same as yours, power packs different.
brown wires are charge coil, white and black are sensor. wires from under flywheel. to check volts you'll need a volt meter and DVA adapter about $22 online,
 

juno pierrat

Petty Officer 1st Class
Joined
Dec 14, 2013
Messages
355
well looking at my last post it didn't post as setup, sensor , ohms 40 +/- 10, min cranking volts 1.5, min running volts 6
charge coil, ohms 575 +/- 25, min. cranking volts 230, min running volts 250. probably won't be able to check running without other special tools.
 
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