Guys,

All back together. New plugs, gapped to .040". New wires from Mosetti. #4 and #7 coil packs swapped with #6 and #5 respectively.

Now we just gotta get it into the water and take it for a ride.

Thanks. Brad.
(937)545-8991

was #4 and #7 producing spark when ran on the hose ? Before ? After ?

I don't understand why you would swap some suspect coils to another cylinder to try them out. Just put your inline spark tester on them and see if they work.

Snap,

We're looking for lost spark under load, and I'm not too keen on running the boat with the sundeck up.

This test should prove if the loss of power is due to lost ignition.

Thanks. Brad.
(937)545-8991

SB,

Other than when we put the boat on the scanner, yielding questionable results, we have not run the boat on a hose. We don't know if those cylinders are getting spark or not. I intend to run the boat on a hose before we take it to the lake and will likely check for spark on all eight while I'm at it.

Thanks. Brad.
(937)545-8991

So by changing the coil packs around you think you're going to tell if there firing by how ? looking at the plugs, I think you're chasing your tail by not having a good scanner hooked up, coils at idle might act fine but under load could be a different outcome, good luck I know you are looking forward to getting this fixed..........what did Pro charger say about the vacuum line ?

F2,

Yes. Advice comes to swap the coils and see if the apparent behavior follows the presumed bad ones. If not, then we are looking at the injectors.

Thats why we are taking it to the lake: To run it hard and put a load on the engine. I think the transition from fouled and wet plugs in those two cylinders to squeaky clean in the same cylinders tells a story. That story, along with the raw gas my friend smelled trailing us leads me to believe our lost HP is due to lost spark, and I am chasing that hunch.

I took it to a marine repair shop to have it scanned, and their lack of capacity to initiate an ignition or injector delete diminishes my faith in their scanner. I asked if anybody would be willing to bring their scanner to the lake, and I didn’t get any takers, so I’m doing it empirically. So far, I’m only out the cost of a set of plugs and a probably much needed new set of wires. And, not that I want to make a career of it, I actually kind of like the problem solving sort of thing, even if I have to fold myself in half to do it. 😎

I have not reached out to ProCharger yet, but I am intending to in the morning.

Thanks. Brad.
(937)545-8891

x 2. Thought this was questioned days ago ?
Very important to find out.

SB,

It was. I own a small machine shop and wear all hats. I’ll get to it. Don’t judge…… 😎

I did get the boat hooked up to some water and ran it in the driveway this evening. All right cylinders are firing at an idle. I did not throttle it up at all, as I was only running it long enough to step back, check for the strobe and then shut it off, trying to keep it cool. Y’all know where those spark plugs are, right….?

BUT……

Since we’re discussing our problems…. My wife had noticed a number of times that the left side exhaust is emitting some light steam at an idle after it’s warmed up. This evening, as I was working my way through the cylinders, starting on the right side, then to the left side, I noticed that the left side exhaust riser was considerably warmer than the right (the exhaust risers are a natural leaning-on spot when you’re leaning in to do whatever). After confirming all eight cylinders were firing, I started it back up and let it warm up. As that was happening, I stepped over the sundeck and hung my head over the back and noticed there was considerably less water coming out of the left exhaust tail than the right. Not NONE. Just less than the other side.

Since this engine is a closed cooling system, I’m not too worried about the engine, as I keep an eye on my gages pretty religiously, and the coolant reservoir is still at a good operating level. but I do have to ask: How is the water routed from the seawater pump? I know it goes through the heat exchanger, and some of it goes through the ProCharger intercooler. But how else is it routed. Is it separated at the seawater pump, right side / left side? Could I have a half-gone seawater impeller? A blockage? 🤨

And back to the initial issue…. This couldn’t be contributing to the loss in HP and top end could it? I know the ECM tracks just about everything, but the engine temp has stayed a nice consistent 160-165 since the day we bought it.

Thanks. Brad.
(937)545-8991

All the 502/454mpis have less water that comes out one side of the exhaust at idle and my tails have a 10-20* temp difference at idle.
Not sure if the 496's are the same.