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1975 mercury 7.5hp no spark

G

got2haveit

Member
I have a 75 7.5 hp Serial #4555695 with a no spark condition. I have completed the troubleshooting test off of the mercury manual and everything seems to point to the switch box. When I disconnected the orange stop wire still no spark. The coils test out at 1700 resistance which is to spec. The HT to ground tests at 1100. The Brown trigger wires test out at 133(140-160 is the spec). Is there anyway to test the switch box before I spend $200 on it.
 
There is no way to test the switchbox.

Once you have ruled everything else out, as you appear to have done, then you "blame" the switchbox...
 
Not sure that the digital meter I'm using is that accurate. With a 5 % error factor i could be within spec. Would that small of a variance cause no spark??
 
I retested the trigger wires with another meter and the reading was 145(in spec). The other readings were pretty much the same. Any ideas on additional tests would be appreciated.
 
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