2007 Optimax 250 ProXS blown coil

[jjbz21]

2007 250 ProXS (1B447058).

Left work early to enjoy some fishing. Was looking forward to a nice relaxing day on the lake. Nope, not happening today. So much for that $20 launch fee.

I launched the boat and tied to the dock and the engine just shut off. It had run fine for maybe 5-10. It would not restart so I loaded it back on the trailer. The first thing I checked were the fuses and sure enough the 20 amp fuse was blown. I tried a spare but not surprisingly it also blew. At that point I decide to head home.

I disconnected all of the coils and installed a new fuse. I connected 1 at a time and hit the start button (didn't crank the motor) until I found the bad one. It was so obvious I should have seen it at the lake, there was a big chunk of hard white material sticking out of the crack in the coil.

Should I be concerned other coils may start going? I may plan to buy 2 or 3 spares just in case.

PXL_20210414_221609461.jpg

[JOE54]

personally never replaced 2 on same mtr unless warranty bulletin requested

[lpugh]

^^^^^^ Yep
Be sure there are no open plug wires, especially on that coil, and replace the plugs if they have close to 100 hours on them

[jjbz21]

Plugs were replaced last year. They have less than 5hours on them. The wires all look good. I tried finding the coil that comes with the wire but no one has it.

The local dealer has 1 coil in stock. They are not cheap at $160.
I'd like to order one to have a spare.

[EuropeanAM]

Coils no longer come with a wire- that was some time ago.

DON'T buy the aftermarket ones- they are NOT the same.

The factory recommendation on your particular serial number would be to replace all six ignition coils now. Yes: Replacing ONE and the fuse will almost certainly return the engine to functioning status.

Keep in mind that when a coil fails in a SHORTED fashion, there is a strong possibility of PCM damage (the primary reason for the recommendation to replace all of them).

Your call, of course- sounds like the ones you have made it a pretty good period.

[jjbz21]

Coils no longer come with a wire- that was some time ago.

DON'T buy the aftermarket ones- they are NOT the same.

The factory recommendation on your particular serial number would be to replace all six ignition coils now. Yes: Replacing ONE and the fuse will almost certainly return the engine to functioning status.

Keep in mind that when a coil fails in a SHORTED fashion, there is a strong possibility of PCM damage (the primary reason for the recommendation to replace all of them).

Your call, of course- sounds like the ones you have made it a pretty good period.

Is there any way to tell if they have already been replaced? What is the reason the the recommendation to change them all? Are they potentially defective or since one went the rest are expected to soon go?

$1000 to replace all of the coils seems ridiculous to me. Especially if they were from a defective batch to begin with. I would think Mercury should have recalled them. I also don't get how a failed coil can take out a PCM? You would think they would have built in some kind of protection in the PCM. I have never heard of that happening in an automobile.

I assume even if a new coils fails in the same fashion there is still a risk of PCM damage?

[EuropeanAM]

There were two service bulletins related to this, SB 2007-25R2 and SB 2009-26R1.

The first deals with testing and explains the possibility of damage to the PCM from a 12V Short-circuit backfeeding.

Replacement of coils was covered under the Factory Warranty period, and in your case until the end of a promotional period that ended in January, 2012. Being as we are now 9 years past that point, you'll need to make your own decision as to which route you take in terms of replacements.

Just the messenger- providing you with the information to make an informed decision.

[jjbz21]

Don,

I am not blaming you I was just venting at Mercury . I appreciate your time and knowledge.

Can you tell if mine were ever replaced via the serial number? Is there a bulk coil discount ��?

Jeff

[EuropeanAM]

I already checked your serial number, and do not see any indication that they were changed.

Simple way for you to tell: Look at the face of the coils, there are embossed numbers and a "Revision" number.

The part number on the later coils will begin with an "8M....". Older ones will be 879984.

[jjbz21]

Thank you.

I see they are all the old part number except the one I just replaced.

[jjbz21]

Don,

Does the BBC discount appy for coils? I bought 2 from the local dealer along with a new set of wires. So I need 4 more or maybe 5 or would it be ok to keep the old ones for spares in an emergency?

[EuropeanAM]

Absolutely it would.

A "currently good" coil is almost always an improvement (as compared to a "currently bad or shorted" coil). So yes, for short term emergency use, but I would mark them WELL to make certain there is no future confusion. Heck... paint them "Caution-Yellow" or orange for that matter.

[jjbz21]

Thanks again for your help.

I just placed an order for 4 coils.

[Z518 Comanche]

Pm sent

[EuropeanAM]

Thanks again for your help.

I just placed an order for 4 coils.

Thank you! Rhonda will get you set up.

[LineCrew]

I was experiencing the same issue with my 2013 ProXS 250. Fuse#4 on the ignition circuit was blowing at startup. Ignition Coil#5 was the culprit. Pin hole on the underside near the plug. Thanks for this thread. It was a great help for me to start troubleshooting.

[EuropeanAM]

[JINXBASS]

Yep I have replaced 5 out of the 6 so far. I always have a new one with me and a few fuses. I can have it changed on the water in about 15 minutes.