9.9 Coil issue

[VeroWing]

I have a 2014 9.9 4str (OR617XXX) that recently would not start after being shut off with kill switch. After much troubleshooting, came to realize coil was bad. Bought and installed new coil and engine started and ran fine a few times. Planned on heading out last week and started engine at home in barrel to be sure all was ok. It was, and i again shut if off with kill switch. Got to water an hour later and engine would not start again. Took it home and once again, coil shows no ohms through secondary wires. What would cause these two coils to fail after running fine and then shut down with kill switch. I checked switches and wiring, and can not find anything out of order. Any iseas on what could be causing this?

 

[gm280]

I have absolutely no idea why stopping the engine via the kill switch could have any issues with the coils. Especially the secondary side of the coils. Are you positive the output spark plug wire isn't the problem coming disconnected from the coil? I can't see what would open up a spark plug coil other then too much current driving the spark plug. But it just doesn't make any common sense. :noidea:

 

[VeroWing]

As it sets right now, when I pull start, test light shows power going to coil. Ohm meter shows continuity between orange wire and black wire going into coil, but zero between either black or orange wires to either of the two plug wires coming out of coil. Also, spark plug tester shows no spark going to plugs when pulling starter cord. This was the same diagnosis with previous coil, and upon installing new coil engine ran fine. At least it did for a couple times. Perhaps I received a defective replacement coil, so I've now ordered another, but at $80+ each, I'm concerned the same will happen with new coil. I researched everything I could find on this, and on one thread there was some mention of a group of faulty coils on Mercury engines, and that they were aware of this, but could not find any real proof of this. Guess I'll just go through all the wiring again, and cross my fingers that something else on engine isn't causing these coils to short out.

 

[gm280]

As it sets right now, when I pull start, test light shows power going to coil. Ohm meter shows continuity between orange wire and black wire going into coil, but zero between either black or orange wires to either of the two plug wires coming out of coil. Also, spark plug tester shows no spark going to plugs when pulling starter cord. This was the same diagnosis with previous coil, and upon installing new coil engine ran fine. At least it did for a couple times. Perhaps I received a defective replacement coil, so I've now ordered another, but at $80+ each, I'm concerned the same will happen with new coil. I researched everything I could find on this, and on one thread there was some mention of a group of faulty coils on Mercury engines, and that they were aware of this, but could not find any real proof of this. Guess I'll just go through all the wiring again, and cross my fingers that something else on engine isn't causing these coils to short out.

Sound like a good plan. However, I would contact Mercury, or the manufacture of your latest coil and tell them about it. You may get a replacement. :noidea:

Your trouble shooting system seems good and I would also suspect the coil even being new. The fact that you have a primary power feeding the coil and no output points to the coil. Don't throw the old coils away until you absolutely find and verify your problem. I know I would tear into them just to see where the open is occurring. But that is how I do things. I'd take a very find Dremel grinding bit and grind away on the coil housing until I got to the windings to see where the open is and to see if it was burnt or what. JMHO

Oh, one other ting. What are you gapping the plugs to? Most are 0.030" but I can't say for certain on your engine.

 

[VeroWing]

Sound like a good plan. However, I would contact Mercury, or the manufacture of your latest coil and tell them about it. You may get a replacement. :noidea:

Your trouble shooting system seems good and I would also suspect the coil even being new. The fact that you have a primary power feeding the coil and no output points to the coil. Don't throw the old coils away until you absolutely find and verify your problem. I know I would tear into them just to see where the open is occurring. But that is how I do things. I'd take a very find Dremel grinding bit and grind away on the coil housing until I got to the windings to see where the open is and to see if it was burnt or what. JMHO

Oh, one other ting. What are you gapping the plugs to? Most are 0.030" but I can't say for certain on your engine.

Foolishly threw away original coil, never thinking this would occur. Contacted seller for second coil, and sent it back to them for replacement, possibly on them. Plugs both have been replaced and gapped as per manual. Thanks for your opinions on this.

 

[VeroWing]

Some good news. Supplier of new coil that immediately went bad, has sent me a new replacement coil at no charge to me. I installed it today, and motor started right up and ran until I shut it down. Also went through wiring again, and all was in order, so hopefully this issue is solved.

 

[gm280]

Some good news. Supplier of new coil that immediately went bad, has sent me a new replacement coil at no charge to me. I installed it today, and motor started right up and ran until I shut it down. Also went through wiring again, and all was in order, so hopefully this issue is solved.

That is great news and show the company does care about their customers. :thumb: