Lost Spark on Hole #3

Crest990

Cadet
Joined
Sep 25, 2005
Messages
16
It's still amazing to see how many experts are on this forum. I've been helped greatly in the past and am hoping for some more help now. I'm still running a 1978 175 Black Max. Saturday the engine became sluggish and wouldn't rev past about 1500rmp. Changed all the spark plugs, still had the problem. Checked spark and found #3 wasn't sparking. Checked coil, worked fine. I'm now thinking of trigger, stator, or switch box. The interesting thing that I don't understand is after sitting for a few minutes, the plug would spark once when first turned over, and then never again until I repeated the process. Very strange...

FYI-the trigger wires were very corroded when I bought the boat 3 years ago. I replaced them all and didn't have any other problems with spark until now. I have had intermittent problems where the engine wouldn't kill after running, almost like half the motor shut off but the other half didn't. I replaced most of the ground wires and still couldn't fix the problem so I've been killing it with the choke. However, whil playing around, I found that the mercury switch would kill it just fine. Any help on this would also be great. I now need to replace the trigger, my last fix is not going to survive any longer. Where's the best place to find one? Also, could this be more than a trigger?

Please help.
 
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