I did it using aeresol window cleaner and lightly fogged over the wires. problem is the coil packs are way at the back and the wires flow down the side/back of the motor where you can't see them till they come back up under the headers by the plugs. Couldn't see enough of the overall wire length to rule out that they aren't leaking where I can't see.

Appreciate the ideas and keep'm coming.

Now I want to see it solved, so I have another vee to run with !! Ok with you to cruise around the century mark ?

I have a set of spare wires on board, plus scan tool (incl. injector tester), etc. if you want to investigate Friday afternoon. You will have to get a coil though, the spare coil I carry is different than your pack.

Well for the run I did a trick that I had read on some various threads and was confirmed by a colleague at Moog. I closed down the gap from .035 to .025 on the #6 cyl that was not doing its share and that brought the starboard back up to about 98% healthy when compared to the port at WOT. That gives me the confidence that it's either weak coil pack or wire(s). Original plan to swap the wires for #4 and #6 and see if the 4 plug went crappy but because I wanted the best out of it for our run this weekend I went with the gap change and feeling good about my decision. My transom smut went wayyyy down now too.

Well the saga continues. Finally got time to change out the coil pack that the #6 plug was on and same thing as previously noted. Starboard not pulling as hard as port motor beyond 4800 rpm. Perfect Storm had a rocker arm nut loosen up twice and each time was a subtle loss of power similar to what I'm experiencing. So pulled the valve cover and I'll be damned if I can detect a problem Who can tell me what the correct procedure is for setting up the rocker arm adjustment? Limited experience says to set crank near TDC of ignition stroke, run rocker arm nut down til all slack is out and then another ??? Portion of a turn to preload lifter??? Help a guy out here 525 guys. Right now I can detect no slop whatsoever although you can twist side to side without much resistance Next step will be to pull the injectors to see if #6 is acting up.

4 years and I'm still trying to diagnose a similiar issue. Completely rebuilt the lower, new cams, all new valvetrain, blueprinted injectors, new coils and wires, new distributor / senor thing, only thing left is the high pressure fuel pump which should be here this week. If its not it, I am stumpped.

Mine is cylinder specific as all plugs except #6 look perfect all the time. It's the #6 cyl that I detected either the spark blowing out and leaving deposits or just a rich fuel condition occurring above 4800 rpm and leaving deposits.

I'm just guessing but try swapping the ecu's from one motor to the other.. At least its a cheap and easy test. I heard something about bad ecu's on those motors.

Good idea. Merc says all the software or whatever is in there was up to date but like you said, cheap and easy test. I'm running out of ideas. I used a Moroso spring tester and the springs on that side were all in spec for force at lift-off. If ECU doesn't highlight anything injector test/clean/test is next.

if you are saying # 6 is rich and that plug is fuely it could be a leaking fuel injector or its pattern is off or it can be stuck open. Any fuel in your motor oil as this 4 sure would confirm that.

If anyone who works on their own boats , one the easiest ways to check spark while running the motor is with totally sealed inline spark checkers by a quality maker. A great tool to have as you can watch each for spark or weak spark while the motor runs. These are totally sealed but can see thru them to watch the spark firing or not.

Hoping the injector test/clean/test yields results