no power to the coil 1973 Merc 65 hp

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Steven1962

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34
Ok here it is. I have 11+ volts to the red 11 + to the white and 11+ to the white/black No power to the coil at all and nothing at the brown, blue or black wires. Needless to say I have no spark. What should be tryed next??

Turns over well fuel on plugs I am thinking it is just an eletricial problem. Should I be trying anything else before replacing the CDI.

Thank you.
 
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Laddies

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Re: no power to the coil 1973 Merc 65 hp

The coil (transformer) has only AC voltage when the switch box fires it, hres the test for the system from CDI.
scan0002.jpg
 
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Steven1962

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Re: no power to the coil 1973 Merc 65 hp

I have this document, for my Motor 3 cylinder and have gone through all the steps. the coil wire does not fire! When touching the blue wire to the ground. But there is no power coming from the Green to the coil either. When grounding the blue wire.

What NEXT?

Thanks Steve
 
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Laddies

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Re: no power to the coil 1973 Merc 65 hp

If the red and the white terminals have voltage and you have placed a jumper between the white/black and the black terminals, if you arc the blue terminal and it don't fire the coil then the swtch box is bad.
 
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Steven1962

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Re: no power to the coil 1973 Merc 65 hp

Ok I bought a new switch box and Impeller I replaced them both. The motor started right up seem to run very well. The high tension lead on the coil wire was arcing, I shut it down right away. Question did the arcing kill the old switch box? What causes a switch box to fail?
 
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Laddies

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Re: no power to the coil 1973 Merc 65 hp

Any voltage surge low or high, a bad rectifier or the battery hooked the wrong way could cause a failure, also age could be a factor.
 
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Steven1962

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Joined
May 23, 2008
Messages
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Re: no power to the coil 1973 Merc 65 hp

Thank You for the info. I guess I will just chalk it up to being old 35 years hhmmm I guess it could of just wore out.

Thanks again Steve
 
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