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1980 J150 V6 loses spark- dies

D

drewzap

Member
Hi gang,

UGH

So i took this boat in trade, shoulda known better but i wanted another boat so here we go lol !!!
1980 Johnson J150 V6, plenty of fuel (new fuel pumps) new plugs, fresh fuel, good compression, good impellor. Starts right up, will idle and rev up, but all the sudden will shut off.. just die. No signs of anything cutting out. I have disconnected the black/yellow wire from the ignition switch, as well as the dead man switch. Odd thing, i can still kill the engine shutting the ignition switch off!!!
Anyways, it will restart immediately or almost immediately..suggestions on where to look??? The fish are biting =(

DZ
 
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The fact that it shuts off after disconnecting wires from ignition switch means that you need to get a wiring diagram and go through it all.-------Something is wrong and if you ignore that fact it can get expensive in a hurry.
 
Ive just gotten a factory manual. The only thing i can see in the harness diagram that affects both powerpacks, is the splice in the magneto kill circuit, and the timer base??
But without a CDI break out box and adapters, I dont believe i can test the circuit running to see what drops out. Do you think it is possible, that a powerpack can be internally grounding out when hot? I did read where if the engine does not shut off with everything hooked up, the ground circuit is faulty in the powerpack. Could the reverse be true being there is a splice to both packs after the main harness connector inside the engine? The fact that in mere seconds the engine will restart is making this a difficult problem to find.
 
YOU say you have the kill circuit disconnected at the switch ( black / yellow wire ) , yet it still stops when you turn the key off !-----------This means that something is wrong in the wiring or the way the ignition switch is hooked up !
 
Ohhh, yes. I checked the harness wiring and colours, and all looks normal according to the book. Shorted wire perhaps in harness?? Ive done a wiggle test throught all accessible harness lengths, disconnected all plugs, cleaned, reconnected. Im under the impression that the engine should be able to run under its own power. Once started, it should be self contained? Meaning i can negate the harness from the "boat" to the engine??? Once i unplug the main harness connector it dies. Only thing i can see is the key supplies power to the voltage regulator on the A (acc) side of the switch. No power there no run??
 
The ignition system on this motor does not rely on 12 volts from the battery.----------It generates / makes spark using the flywheel magneto.
 
Thats what i thought. However, if i disconnect the main harness, it dies and will not restart until i reconnect it....That is probably the fault i am tracing???
 
ok..figured it out!!!
after tracing every wire on the engine yet again, i found 4 wires not in my manual. Turns out, someone started installing a VRO system on this non VRO engine, and that was killing it. After disconnecting the 2 EXTRA black/yellow wires, the intermittent grounding issue was no longer present!!!
I may look into eventually hooking that up correctly, but for now, I'll pre-mix and go see if she floats!!
Thx for the help yet again
DZ
 
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