I have a 1969 20hp Mercury outboard. It ran when I stopped using it about 10 years ago. I've been trying to get it

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Customer: I have a 1969 20hp Mercury outboard. It ran when I stopped using it about 10 years ago. I've been trying to get it running but I can't get spark., I have changed the coils, plugs, and plug wires, tested the capasitors and still no spark. Any ideas?
JA: Sometimes boat issues seem like they'll be really complicated, but end up being easy to fix. The Marine Mechanic I'm going to connect you with knows all the tricks and shortcuts. Is there anything else the Marine Mechanic should be aware of?
Customer: I don't think so.
Answered by Yachtwork in 3 hours 2 years ago
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Specialities include: Marine mechanic, Diesel Engine Repairs, Boat Body Repairs, Boat and Watercraft Repairs

Hello- Well there is not that much more to the ignition system to check. The stater is next. You can do a resistance check by just pulling the wires from the stater.

Here is the resistance test specs. We have to look for your exact Merc but if you can't find it we can get an idea from a similar model. Look Here.

I was not able to pull up your exact Merc wire diagram but here is one listed a couple years later. See it here.

Does this look like what you have? No points but the early version of the control box. If so then we need to figure out how to test the control box. That particular box is suspect because even though they don't label what it is, or what Merc calls it, it is wired like a nearly CDI unit and that is getting pretty old for the capacitors to keep firing. First check the stater, then we can move to the CDI box testing.


I forgot to tell you....I have cleaned the surfaces of the stater with 10,000 sandpaper and points.... didn't set the points because it was running when i parked it....and tested the resistance and was good. I also checked out the kill switch. Question:The motor does have a starter and selonoid plus wiring, but I don't have the ignition side of that. Could it be that that wiring could cause it not to spark, or possibly a bad selonoid, even though i don't start it with a battery and ignition. I did however notice that the little wiring that there is is not bright and shiny .....the copper is brown in color. The only other thing I can think of is the possibility that when I replaced the plug wires I didn't push the wires into the new coils far enough to make contact.
I dont think a call is nessary....I also think we covered all the bases...

Thanks for the extra info. The call prompt is a system thing. It does not come from me and you are right would not help much either.

to answer your question, the engine should run just fine if you pull start it and don't have it hooked to the battery. The stator has two windings. One for battery charge and one for the ignition.

Let me know how it turns out.

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