I am really disappointed as there was complete rebuild done and today I called the guys if they inspected injectors and ofcourse the answer was no. Next to does are: check the spark on all cylinders, checking the injectors, checking fuel filter if there is some paint inside…

The rpms are around 4500 at 47 mph… but there is really no power…

Vidic,

How does it get to 4500RPM? is it really sluggish? Take forever to get on plane? Or is it at least strong-ish to that point, then hit a wall?

At 4500RPM, I am running ~70MPH GPS. At 5100 RPM, I'm topping 77MPH. I understand you're running WAY less prop pitch than I am, but I think this is indicative to your actual problem. If you've read through the thread I posted, I had propped down to make the boat behave better, masking the actual problem, until I couldn't ignore it anymore. I had a strong smell of gas in my exhaust, too, and I was down one cylinder, and one limping along. I'm betting the seller you got the boat from had done the same thing, only FAR more drastically. A 21P prop is WAY to small for a 496HO on a boat your size. My boat, without the ProCharger, would likely be running a Bravo26P, and be somewhere in the 65MPH range, at 4800lbs dry weight. Yours should be considerably lighter, making that prop easier to turn.

If I had to bet, I'd say you've dropped a couple cylinders, either ignition or injectors.

Like I said, find or buy a Techmate. It will make this process SO much simpler. It will allow you to perform a cylinder delete, one at a time, both injector and ignition, without reaching your hand into the engine bay.

Thanks. Brad.

Hey Brad,

I was reading and reading and reading all the conversation in your thread. I am 99% sure it is exactly the same problem as you had it. I have to do the test on the injectors as engine sounds healthy and I would say that there is a spark on all cylinders. Firstly I will check if there is spark on all cylinders after that all the injectors are coming out… I found also how to take the injectors out it on your post…

I will do that on the weekend Keep you posted.

Vid

Vidic,

Have you looked at your plugs? Do yourself a favor and put new plugs in it, take it out and run it as hard as it will run for a couple minutes, then put it on the trailer. Sometime after it cools off, pull the plugs. As you do, write the cylinder number on them and take a pic of them. This will tell you which cylinders are not firing, or loading up, or whatever, if misfire is, indeed , the case. I went through four sets of plugs before I finally rooted out the problem.

The biggest issue with getting the injectors out is the coolant reservoir that is just enough in the way to get the fuel rail off. If I were spending your money, with the age of your engine, I’d plan on replacing the coolant reservoir, as, with time and heat cycling, it will have have become brittle. As you read, I cracked the down snout on mine trying to get it out of the way to get the fuel rail back in. I was able to acquire a new one while the injectors were in process with Smitty (ArcticFriends), and it wasn’t really that expensive. Not that I would have just replaced it otherwise, it is definitely worth the peace of mind, knowing it’s new now.

Also note that I ripped the O-rings on at least two of the injectors putting them back in the first time (when I cracked the coolant reservoir), as they presented a TON of resistance going in. Going back in the second time, with some dielectric grease on the O-rings and in the injector ports, they went in smoother as silk.

Just trying to help you avoid some of the pitfalls THIS rank amateur suffered through.

Thanks. Brad.

First of all I want to thank you for such a fast replies. In Europe people are not willing to help each other. So I really appreciate thanks!… the plugs have 2 hours so I will check them how they look. I will also take some pictures… yesterday when I was doing the fuel pressure test i also put a little bi asside the reservoar… I will also check it thanks… haha I already took all the screenshots where you had problems. What about fuel economy was it bad at that time and second question is was there a gas smell from the exhaust?
thanks

Vidic,

Yup. I noticed the fuel pressure fitting was kinda tricky to get to.

I do not recall any significant changes in fuel economy, but I was not really monitoring it to begin with. I’d have to assume we were consuming more fuel, as it was a long, full throttle affair just getting on a plane.

Yes. There was a fairly strong smell of gas in our exhaust. A friend specifically mentioned it after trailing us on the water.

FWIW…. My untrained ear couldn’t detect any loss of cylinders, idling through full throttle. Thinking back, it does sound different now, but, at the time, nothing seemed out of place.

Thanks. Brad.

I am just hypothesizing, but I believe what would happen if paint got into the injectors, is it may not plug them up enough to stop the engine from running, but could disturb the spray pattern, resulting in large droplets of tuel instead of a fine mist. Those large droplets would not completely burn, and result in the strong fuel smell you are getting out the exhaust.

Injectors are out so they will be tested in this week I will report on the outcome but I really think this is it… today I will also put down the cool fuel system so we can open it and check for the paint problem… I started the session very bad I had to change several things the last two are hopefully gasket between the engine and exhaust, cool fuel system and the injectors test and rebuild… thank you all.!
Vid

Vidic,

Ain't boats FUN! 😍

Do yourself a favor and, while you're waiting for your injectors to come back, go to an automotive shop and get a packet of brake grease. Those injectors will not want to go back into the fuel rail dry, and you may end up tearing one or several of them trying. A thin layer of grease on the O-rings and in the injector seats in the both the fuel rail and intake manifold will allow them to slip right in, making the reassembly SO much easier. Plus, some fuel resistant sealant never hurts.

Also.... While you're waiting.... Disconnect the fuel supply line from the tank and pump about a half gallon of "new" fuel through it into (preferably) clear glass jar. Inspect the fuel for debris. If you get debris, empty the jar and do it again. Repeat until you get clean fuel. If it doesn't clear up, you've got debris in your tank, and it will need pumped out and cleaned. Once you have a clean fuel supply, replace both fuel filters and reconnect. I'd suggest letting the boat sit, with the hatch up for at least a day before thinking about hitting the key, to allow any spilled fuel time to evaporate. There is sure to be some.

When you get it all back together, before you attempt to fire it up, turn the key to "run", then back to off, several times, until you get a consistent fuel pressure reading and gage behavior at the fuel rail. It might go really high initially, then drop to ~40psi and hold. When you fire it up the first time, you should expect it to run like crap for a minute while the fuel rail populates with fuel. Remember, the fuel rail is a fuel tight chamber that is initially full of air, and the injectors are just doing what they do, which is to fire tiny shots of fuel (air at first) at a time. When the fuel rail populates, it should run much more smoothly. I'm pretty sure mine was running on about three cylinders when I first fired it up. Give it time.

Once you have good fuel flow and the engine is running, you should verify spark in all eight cylinders. A spark tester is cheap. It goes between your spark plug wires and the spark plug and has a strobe to indicate spark. Pick one up while you're getting your brake grease.

Thanks. Brad.