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Spark comes and goes

G

griffinr

New member
Hello,

I have a Mercury 70 hp 3 cyl. The spark comes and goes. It's almost like a bad wire. I've replace the switch box but it didn't change anything. I can start it, shut it down. back it in the water and it won't start. Pull it out, check the spark and nothing. Any ideas?

Thanks,

Bob
 
Hi,

Thank you for getting back to me. I'll give this a try and let you know how it turns out.

As for the year, I believe it's a mid 80's engine.

Thanks again,

Bob
 
Having similar problems with my similar motor. Starts fine cold--even runs fine for a half hour or so, then craps out if I idle it down. Then doesn't want to restart--it tries to go, but doesn't quite make it. (Had to get towed in, blast it!) Let it along overnight and the cycle starts all over again.

Stator is CDI (2 years old) as is the switch box. My DVA meter says all is well (after sitting, when it runs okay again). Need to take the meter along and wait for it to screw up again. My best guess is a heat related switch box failure, but CDI says that's not common; "They either work or not."

Stay tuned: I'll let you know if I find what's causing this.

Jeff
 
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