Mercury 50 Ignition

JDusza

Ensign
Joined
Apr 21, 2009
Messages
952
Mercury 50 hp, 3 cylinder, OA987473, that has no spark at any of the plugs.
I found a master ignition switch on the shifter / throttle housing, but, still no fire.
I disconnected the black / yellow stripe wire from the switch box; still no fire.
What else could kill all 3?
Thanks,
J
 

JDusza

Ensign
Joined
Apr 21, 2009
Messages
952
Re: Mercury 50 Ignition

Disconnected the black with yellow stripe wire from the switch box. This wire comes from the main harness connector.
Disconnected the black wire from the switch box. This wire comes from the trigger assembly.
Connected DVA and meter to each coil's input.
Measured 0 vdc at all 3 coils when cranking engine.

Swapped switch box and retested.
Measured 34 vdc at each coil.

It appears the switch box made a difference. I hooked up my spark tester but between the daylight and me being 6 feet away at helm, I cannot see spark. The battery is dead enough it will not crank with compression. The battery is charging and I plan to go back in the evening when I can see sparks fly.

When cranking, with DVA attached, the violet trigger measures 3.8 vdc, the white trigger measures 3.3 vdc and the brown trigger measures 4.0 vdc. I think this indicates good triggers, although not perfect at 4 vdc

When cranking, the red stator lead measures 34 vdc with DVA and meter. The blue stator lead measures 34 vdc, as well. So, I think the stator is putting out signal.

Does this make sense to anyone?

Thanks,
J
 
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