1973 Mercury 7.5hp no spark

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mike12

Seaman Apprentice
Joined
Aug 4, 2004
Messages
32
I have a 1973 Mercury 7.5hp outboard that i can't get it to spark on either cylinder. So far we have replaced the points and plastic insulators,put in new wiring new low and high speed charge coils and a new ignition module.The old module had a burn spot in it.Any suggestions would be appreciated. Thanks
 
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emckelvy

Commander
Joined
Jan 16, 2004
Messages
2,506
Re: 1973 Mercury 7.5hp no spark

Maybe it's got a bad kill switch? Disconnect the kill wire to eliminate that possibility.<br /><br />Usually it's pesky points conn insulators, killing the spark by shorting thru to ground. Is this the type with the ign module under the flywheel? I assume it is, anyway. That type of ign also has a capacitor which can go bad. <br /><br />Failing that, the only other thing I could think of would be 2 bad coils, a pretty rare occurrence.
 
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mike12

Seaman Apprentice
Joined
Aug 4, 2004
Messages
32
Re: 1973 Mercury 7.5hp no spark

I've already disconnected the kill switch and we tried two coils off another motor. we also used another condenser off the other motor and that didn't work.yes your right ign module is under the flywheel. guess i'll try the points again and insulators? Thank You for your help. Mike
 
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Tomxx7

Cadet
Joined
Jan 4, 2004
Messages
20
Re: 1973 Mercury 7.5hp no spark

If your engine has maker points then the kill switch needs to be connected. The ingnition needs to be grounded. Its reverse of the old type kill switches which grounds the Ing. to kill it. Yours disconnects the ground to kill the engine. You may have fixed it and just need to reconnect the wire. Also make sure the switch is working proper. Tom
 
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