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No spark 87 35hp Merc

J

JonnyBoats

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I recently bought a used tracker with a 35hp Mercury with controls. I got it to run. It had been sitting for a year or so. Then it stalled. I noticed a lot of crud in the fuel filter so I replaced the filter and cleaned the carb. Thinking that would do it. All of a sudden now I have NO spark. I tested everything. Stator is giving power. Power doesn’t leave the Powerpack it seems. I swapped a new power pack and still nothing. I’m also getting power to my grounds somehow. I tried removing the kill switch wire but that didn’t do anything. Am I missing something? I tested everything according to the service manual for a Type 4 ignition system. The motor ran even when the killswitch was set to off or run so I’m stumped.
 
Serial Number is 6579354. If anyone has any idea where to start would be greatly appreciated. I did remove the CDI from the mounting bracket in order to get to the carburetor. I believe after that is when everything went wrong. I did put everything back where it was supposed to go.
 
Check the wiring for decayed insulation, touching metal somewhere, very common on older Mercs. This may explain why you are getting voltage through the grounds. What method are you using to read voltage at the grounds?
 
While turning the flywheel? The only voltage generated is rotating the flywheel. Unplug the wire harness to divorce the starting circut from the running circut, then do your ground tests. Pull the motor over from the rope groove on the flywheel.
 
It’s an electric start. It has voltage on the grounds without touching the key at all. I’m going to be testing the rectifier tomorrow and seeing if it stops the short it’s the only thing I can think of that I touched when moving parts around to get to the carb
 
I feel pretty dumb. I was touching both leads to ground. Which would make the beep on the meter. I thought that meant a short. So now back to square one. I checked rectifier and it checks out fine. Going to replace it bc it looks a little rusted in the contacts. But still no spark. Trigger Ohms read at .738 when they should be around .8-1.0 (Rx100 setting my meter sucks) stator test doesn’t make sense on the manual but the values I’m getting are 49.7 and they should be between 45 and 60. Both coils read good. I’m assuming the trigger is the issue.

But does anyone think the low value in the stator means it’s heading out the door? Is it worth replacing while the flywheel is off? I’m just short of saying screw it and buying an entire new ignition system but I’d rather not.
 
fitz73222 said:
While turning the flywheel? The only voltage generated is rotating the flywheel. Unplug the wire harness to divorce the starting circut from the running circut, then do your ground tests. Pull the motor over from the rope groove on the flywheel
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I wrapped the rope around and gave her a pull. No spark still. When I did have spark it was a little weak. Coils tested fine tho. Not great but fine lol
 
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