2007 mercury optimax 150hp coil issue

[RiverRat318]

I have an 07 150hp optimax (2.5L)

Serial - 1B533319

Last fall, I noticed a drop in rpms and difficulty turning over motor. Tested coils and then found #4 was dead. Changed it out, but in the process, noticed that the coil mounting bolts were stripped. I cleaned threads and snuggled them hand tight for the new coil. Took the boat out for a run and it ran well. Next time out, coil out again. Opened the cowling and found that same coil hanging loosely. I have not had time to test it (ice everywhere here). My questions are multiple:

Even if the wiring harness for the coil is snug, do I need to helicoil this asap?
Could ziptying it to the mounting block work?
I also read that for some optimaxes, they reccomend changing out all coils at once, does this oblige for the 07 model as well?

Thanks in advance. I look forward to being here at this forum.

[EuropeanAM]

If you would, please take a moment to review the Announcements at the top of the Forum, and be sure to provide the Required Info (serial number) when posting. Thanks!

This info will be critical as there were changes in the coils/drivers over the years, as well as how they secured.

[RiverRat318]

Edited initial post with serial
1B533319

[EuropeanAM]

Probably not enough material there to helicoil. Personally, I would replace the plate (884271) and any questionable hardware.

The other option would be to use threaded rivets to replace the threads.

Better check the plug condition for that coil, as well as the plug for the coil harness for any signs of melting, damaged or loose pins.

[RiverRat318]

I inspected all wiring for coil number 4 and found no signs of melting or any damage. Pins are all clean and intact. I'm assuming that the looseness of the coil caused it to burn up??? Ordered a couple more coils. You mentioned riveting the bolt, but how difficult would it be to remove if the coil needs to be changed again? (Never used rivet gun)

I'm also wondering if a grounding issue could be causing the same coil to fail. Where would this be located?

[EuropeanAM]

Make sure you are using the CORRECT OEM Mercury/Quicksilver coil. DO NOT use aftermarket, and do not use anything other than the latest/greatest part number.

Coil bouncing around might have damaged, possibly. Grounds are common on the coil plate (physically attached to the coil plate itself).

[RiverRat318]

I've been ordering coils from amazon. They fit and are supposed to work for 150 mercury optimax 2.5 L...
Perhaps I should order OEM
On my existing (good) coils, they read
0967
883778
Rev-B

I've googled this and could not find an exact match...

I've found the rev A coils with same serial number but nothing matching the existing ones

[EuropeanAM]

Order a new OEM coil. 8M0077473 only.

This is one of the reasons we don't support parts/purchases from the "zon" or the "bay" here in the forums.

[RiverRat318]

Just ordered. I will update when part comes in and I have a chance to run it. Thanks

[JOE54]

Order a new OEM coil. 8M0077473 only.

This is one of the reasons we don't support parts/purchases from the "zon" or the "bay" here in the forums.

^^^^^+1