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1988 johnson 40hp no fire to plugs

I have a 88 Johnson 40hp. it was running fine one weekend next weekend never would fire. I have no power going to either coil. im not sure how to test charger coil or the sensor assembly. can anyone give me tips on what to check
 
The first thing I would check would be the battery connections on both ends ma sure they are shiny bright and tight. Have you had battery load tested? If the engine is not spinning 250/300 rpms then thee will be no spark to check. Good luck
 
How did you check the rpms? Did you get the battery load tested?
Did put a load tester on battery. Battery checks good. I also hooked battery charger up with starter charge on. Motor was spinning a lot faster than it normally does to start. I changed switch box yesterday still no luck. I'm getting voltage out of charge coil. Also getting that .5 volts it says u have to have for trigger
 
I would be taking the starter apart for inspection and a simple ohm check on the armature.------Very simple to do.
 
Assuming that the engine is cranking over at least 300 rpm..................

With the spark plugs removed so as to obtain the highest cranking rpm..... disconnect the black/yellow wire from either the ignition switch or the power pack (whichever is easiest) to eliminate the kill circuit. Test to see if spark will jump a 7/16" gap.

If you have spark with that wire disconnected BUT no spark with it connected, replace the ignition switch.

If, with the black/yellow wire disconnected you still have no spark, the cause is normally a failed powerpack. Should this be the case, also check for the following voltage problem.

Voltage To Powerpack Failures
(Magneto Capacitance Discharge Systems)
(J. Reeves)

The usual cause of having those type powerpacks fail repeatedly is having a very small of voltage applied to the Black/Yellow wire (Kill Circuit) at the pack. Test as follows.


Disconnect the Black/Yellow wire at the powerpack.


Insert either a ampere meter or a volt meter set to its lowest DC voltage reading between that Black Yellow wire and ground.


With the ignition key in the OFF position, observe the meter reading. Now turn the ignition key to the ON position and again observe the meter reading.


Any reading, movement of the meter needle, even a microvolt, would indicate that battery voltage is being applied to that Black/Yellow wire. If a reading is present, remove the other end of that Black/Yellow from the raised terminal of the ignition switch.


If the reading ceases to exist when the Black/Yellow wire is removed from the ignition switch, replace the switch. If the reading continues to exist, there would be a short of some kind in either the engine or instrument wiring harness.... to determine which, simply unplug the large RED electrical plug at the engine which would eliminate the instrument cable.

Note that the black/yellow wire must not have any other wire attached to it for the following reason!


Keep in mind that any accessory that has 12 volts running to it, especially when turned on, will have voltage flowing thru it and trailering out thru its black ground wire to complete the circuit. If that accessory has it's black ground wire attached to the "M" terminal that the black/yellow wire is attached to.... you will have voltage flowing directly to the powerpack.

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i have completely unhooked kill wire a cdi box still nothing. can someone tell me how to check the sensor assmebly. its a brown piece under fly wheel it has a black/white wire and a white/black wire. i have checked voltage between the brown wire and the brown/yellow wire im getting 200+ volts from it going to cdi box. i have no power coming out of cdi box going to either coil
 
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