Need help please 70hp Johnson

Derrick O

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Jul 7, 2025
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I could use some help please. This will be a little long but is all relevant. I have a 1990 nitro with a 70 Johnson on it. Ihe boat set for about 2 years. I decided to fix it up as I really like everything about this boat (especially no payments). Had a small hiccup with losing fire. Not sure why but could unplug the red connector and it would fire. I can plug it back in and it would work with the key until the next time is decided not to. Thought everything was okay motor running fine no problems until I changed a couple gauges out. After changing the speedometer the tachometer and the fuel gauge went to start the motor again no fire unplugged red plug still no fire. Had a spare motor that Ran very well took the stator all the electronics off that motor put on my motor still no spot with or without the red plug being unplugged any ideas guys this thing is driving me up the wall. Any ideas would be very much appreciated.
 
Does it have spark when connected and/or disconnected? It's common for the wiring or ignition to have loose or broken wires that stop it from getting spark. If you disconnect it and there's still no spark you have other problems too. And you could have two separate problems that could keep it from running, one in the wiring harness after the red plug and another one on the motor itself.
 
Before if I unplugged the red plug it would fire. I could then plug it back in a it would work. Now I can't get it to fire unplugged or plugged. It also acts like it has a weak battery and it doesn't. even with a charger on start position. I am at a loss. Any ideas would be great.
 
You didn't answer whether it was getting spark when it was plugged in and unplugged.

You may also have corroded battery cables, use jumper cables to bypass the existing battery cables.
 
I have no spark, plugged or unplugged
 
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If it's not spinning fast enough it won't spark. If you didn't connect a ground wire after you replaced everything it won't get spark, actually anything not connected correctly may stop it from getting any spark.

If it ran unplugged prior to you replacing a bunch of parts, thats most likely where the problem is. You had one problem to start with, now you have two.
 
The wires from the stator were reversed. I couldn't see the gray strip. I would like to think each of you for your suggestions and input.
 
It looks very much like a concern for beam or mass, especially since it started after the change of meters.
I would first check the wiring behind the switchboard and the shutdown switch that could turn off your ignition.

 
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