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99 merc no spark on one cylinder

R

rainbro

New member
"running on one cyl.swapped sp

"running on one cyl.swapped spark plug still no spark,swapped wires to coils now other coil sparks.I removed green/yellow going to coil and attached test light.pull engine ,test light lights. Connect to other wire green/white(to coil) there is no light on the tester.I disconnected what a would call the magneto and got 2.69k ohms.I disconnected the ignition pick- up and got .776k ohms.The magnets on the flywheel both have magnetism. I do not believe it would be the pick-up or magneto as it does have spark on one cyl. anybody with ideas? how are the ignition modules on these things? thanks"
 
"Robert,

I do not know whic

"Robert,

I do not know which year we are talking about, but I am assuming it has a switch-box (power pack), and that has to be the problem.

Tony"
 
sorry it is a 1987 .What could

sorry it is a 1987 .What could cause this to "blow".This motor supposedly had a running concern when it was given to me.I took it to the lake it ran perfect.The next time i went out it ran on one cyl
 
"Robert, I would agree with To

"Robert, I would agree with Tony. It is rare for these little Merc's to blow a Switch Box, generally an extrememly reliable part, but that certainly sounds to be your problem based on your testing results."
 
The switch box is relable but

The switch box is relable but has finite lifespan and is predictable that way. Your motor is ~20 years old and that is about right for those switch boxes. Just my observation over the years.
 
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