150 Optimax no spark on #4

[styler]

2004 150DL hp Optimax ser. OT862351

I just got this boat a couple weeks ago and thought I was having a prop issue. Turns out I'm down on power. Checking things today I found #4 not firing.
Thought it was bad coil, but I swapped the wires from #4 to #6 coil and #6 to #4. Can't swap the coil physically without pulling the whole coil plate.
#4 coil has spark and # 6 don't. so, the coil is good .. put it back where it belongs.
As I understand it there's a crank sensor that tells it to fire each cylinder. But # 4 isn't .
Anyone have an idea of where to go from here?
I have a mechanic friend who Is coming fri eve to help . He can hook it up to his laptop and run some diagnostics but in the mean time if i can trace it . Well yall know. I want to find it lol.

Also I did some more researching and it has dual coil drivers. can these cause one cylinder to fail?

[styler]

Well no response here but ill put a close to it anyway. Maybe it'll help someone in the future . After swapping the coil drivers and the problem followed the driver we found thats the issue . I have one on order so should be good.

[EuropeanAM]

Note that the drivers are not necessarily correlated to the pair of coils they mount with.

Your original statement was that you swapped the wires on the coils (4 and 6) and problem MOVED to #6. This would also point to a potential driver problem.

[styler]

Note that the drivers are not necessarily correlated to the pair of coils they mount with.

Your original statement was that you swapped the wires on the coils (4 and 6) and problem MOVED to #6. This would also point to a potential driver problem.

Thanks Man.. I got the driver and it fixed my issue .Engine is running great now . the driver mounted on the top set of coils (1 and 2) runs the coils for 1 and 4 so it had me messed up for a bit until I found a diagram .

[styler]

Pulling my hair out. Engine ran great for 3 or 4 fishing trips. last night it failed. coil driver for cylinders #1 and #4 shot again. In my testing and swapping last time I had moved an original to this spot and the new one went to #3 and #5 coils. so the new one is still good.
Any ideal of what would cause a duel coil driver to fail?

[EuropeanAM]

Bad coil, incorrect spark plugs, bad wires, or possibly none of the above (just a wiring/connector or harness problem).

Also... make sure you remove that coil and inspect it from the backside for any signs of leakage (spark jumping around or through the case of the coil). Have seen a couple that would come-and-go leaking through the case, but you could not see it until you removed the coil plate and the coil.

[styler]

Bad coil, incorrect spark plugs, bad wires, or possibly none of the above (just a wiring/connector or harness problem).

Also... make sure you remove that coil and inspect it from the backside for any signs of leakage (spark jumping around or through the case of the coil). Have seen a couple that would come-and-go leaking through the case, but you could not see it until you removed the coil plate and the coil.

Thanks. I bet your right on the bad coil. since #4 was the one out last time and now 1 and 4 . the common denominator is #4 coil . Ill change that one and the driver and see what happens. You can bet ill have a spare driver on board from now on.
also these are the spark plugs i put in it are these right ?

>EDIT- ANNOUNCEMENTS<

[SilverFox579]

NGK IZFR5G (NGK item #5887) is the correct plug but note the "zon" and "bay" are not supported here.

[styler]

NGK IZFR5G (NGK item #5887) is the correct plug but note the "zon" and "bay" are not supported here.

thanks and sorry about the zon . ill not use it again.

[styler]

Anyone know how to correctly ohm test these coils? I ended up purchasing a used complete assembly thinking ill swap that whole thing and if it works then, good and ill have spare parts .. but i would like to test all of them to see where i stand . I really feel like the #4 coil is causing the driver to go out but other than parts swapping I cant verify this theory

[styler]

If I test like merc says i get nothing on the green stripped and ground (black) terminal on all coils but if i test green strip and red stripped, I get around.8 on all coils. Is it possible merc got this wrong in the manual?


the high voltage to ground tests in limits on all coils.

any way because all of them test the same I'm assuming that test is good. And since I would get an occasional shut off /back on when running I'm assuming the coil is going in and out which probably shot the driver.






<EDIT- COPYRIGHTS>

[EuropeanAM]

Reference Service Manual (PRINTED, PAPER COPY- MERCURY DOES NOT OFFER ELECTRONIC COPIES TO CONSUMERS).

[styler]

Reference Service Manual (PRINTED, PAPER COPY- MERCURY DOES NOT OFFER ELECTRONIC COPIES TO CONSUMERS).

where would i get one of those?

[leonreno]

Any Mercury dealer including Don above, there is a parts link in his signature, or call his office and order over the phone.

[styler]

Any Mercury dealer including Don above, there is a parts link in his signature, or call his office and order over the phone.

Thanks I did call the office and was told to email the parts department. did that waiting on a reply

[EuropeanAM]

Rhonda will be with you as soon as possible- she's slammed at the moment (partially due to the upcoming holiday).

[styler]

Thanks Don