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Testing a switch box

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gxtro2001

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I have a 1973 65hp mercury. I

I have a 1973 65hp mercury. I was told the switch box is bad but I hooked it up today and pulled the wire from the coil put a jumper wire in it and placed it near a ground and when i turn it over it has a really strong blue spark ! now I have no rotor in it so i can not tell if it will start just yet . but if I have spark coming out on the coil the box should be good right ?
 
"Troy, that was a somewhat ing

"Troy, that was a somewhat ingenious way of checking it out


The switchbox is one of those items that is tested by proving "nothing else is wrong".

But it's primary function is to store and convert power from the stator. Your "test" seems to prove it is doing that at least to some degree.

Switch boxes on Merc's (unlike the powerpacks on OMC's) are not overly prone to failure - at least at nowhere near the same rate, so before ever blaming the switch box, check the entire ignition if there is a problem..."
 
thank you Graham Lamb .( I

thank you Graham Lamb .( I watch McGiver alot . LOL)

once I get the rotor back in I will be doing some more testing. I seen a few fraed wires that could pose problems too wich is my poject today .
 
"Frayed wires are never a good

"Frayed wires are never a good sign - could be grounding out, arcing between each other etc - especially if they are around the switch box - not a good thing...."
 
"Troy, the mercury switch is a

"Troy, the mercury switch is another "safety" switch. It's design is to ground out the ignition if the motor is tilted (to prevent a dangerous start - same idea as the neutral safety switch).

So if that is grounding out on you because of a fray all the power in the world coming from the switch box is simply going to go to ground on the head."
 
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