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2003 15hp Mercury 2 stroke tiller drive weak spark

Lakebound51

New member
So I was out fishing with boat trolling. Went to leave spot and engine was running on one cylinder. Thought I had just fouled plugs so I changed both plugs with proper NGK part#. Did not solve issue. With further diagnosis I saw it had really strong spark on top than bottom cylinder. The plug wires had never been replaced so I thought that would be a good place to start. Still did the same.
I swapped the wires over from one coil to the beside it thinking it was a weak coil. The problem followed the wires coming off the CDI box going to coils.
I pulled the flywheel off to inspect stator for and burn marks. Looked ok. Put flywheel back on and pulled engine over checking with Mac multimeter on leads going to CDI. I had voltage on green wire with white stripe but nothing coming off white wire with green stripe. So I replaced stator with identical Red stator housing. Still weak spark on bottom cylinder.
My question is it possible the capacitors in CDI box are failed for the one lead going to the coil for bottom cylinder. Running out of parts to change.
 
I would buy a mercury service manual and start trouble shooting
verses buying parts that you don't need. It could be as simple as a loose
electrical connection
 
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