Modern 350 Marinizing

Discussion in 'DIY Marinizing' started by LMannyR, Jul 8, 2007.

  1. LMannyR
    Joined: Jul 2007
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    Location: West Palm Beach, FL

    LMannyR Junior Member

    I've read the DIY Mrinizing quite a bit. I've learned quit a bit from the forum as a result. There hasn't been a thread that talks about marinizing modern engines with the electronics (ecu, sensors, etc). What happens to the electronics? Without the electronics, does efficiency/economy/logevity reduce?

    Gonzo - Yes I know that it will be cheaper to "just" rebuild an old marine engine. What are good sources for such used engines?

    I'd like to marinize a 2005 - newer engine. Aside from the list below, what else needs to be done (specifically the electronics).

    (Gonzo's list from http://boatdesign.net/forums/showthread.php?t=1650
    Thanks!!)

    *carburator has bowl vent into the throat
    *fuel injection system is of the closed type-no fuel return line
    *starter is ignition protected
    * alternator is ignition protected
    *fuel pump, if of the diafragm type, has double diafragm and overflow fuel line into the intake
    *gaskets with metal mesh or sheet are stainless steel
    *coolant circulating pump has stainless steel shaft
    *valves are stainless steel
    *freeze plugs are bronze
    *camshaft is of the correct torque curve design for the application
    *Intake manifold, if aluminum, has bronze inserts on water passages
    *oil pump is high delivery
    *pistons are high performance-designed for extended high RPM service
    *Marine blocks and heads have nickel added to the alloy for corrosion resistance and toughness-not necessary but desirable
    *roller type timing chain

    I know there are lots of questions but I didn't want to start a thread for each one. Thanks in advance for any help given.

    Luis
     
  2. Frosty

    Frosty Previous Member

    There are a few people on this forum that would disagree with that compehesive list, I am one of them.

    However it does mostly depend on what you want to do with the engine. I mean a little tootle round an eclosed lake or off shore fishing.

    There has just been and interesting discusion on electonic injection or carburettor, I have to say that the carb came out the winner for a boat engine at this particular time.

    This being the case all your oxygen sensors and the like become uneccesary.
     
  3. LMannyR
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    LMannyR Junior Member

    The Rig will be dropped on a 23' Renken Seamaster (cuddy, walk around). The boat will be used for Intercoastal cruises, possible going 10-15 miles out for fishing, maybe skiing, etc. It'll be a family activity boat mostly.
     
  4. tuantom
    Joined: Jan 2005
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    tuantom Senior Member

    What was the original engine in the boat? If the original engine and the new are both, for example, small block chevys, you're half-way there.

    Most of the auto electronics out of a modern engine will have to go as its computer can't adjust to what you're asking. I looked into this about a year ago; and in the end I put all the original carbureted components onto my new engine. The thread Frosty refers to lists some of the manufacturers of throttle body systems - but, IMO, the cost far exceeds the benefit. If matched up properly, carbureted boat motors actually run pretty clean. That said - If you can salvage a complete fuel injection system from a wrecked boat, and the price is right, that'd be an attractive option.
     
  5. LMannyR
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    LMannyR Junior Member

    tuantom,

    Currently, there is a 5.0L carb V8 Yamaha. I believe thats a small block chevy.

    How can I match the following "right" to run clean?

    Thanks for the response.
     
  6. tuantom
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    tuantom Senior Member

    When I say burn clean, I just mean boats aren't subjected to frequent squirts from the accelerator pump like a car would be. That extra squirt of gas every time you hit the gas was responsible for a lot of the carbon build up and higher fuel consumption. When running at steady rpm's, a carb could be fairly efficient.
    The right setup is just a carburetor calibrated for your engine's needs. The one you have may work with some tuning, I don't know as I've never worked with a Rochester; but a manual can tell you specs. The easiest way is stick to whatever Yamaha put on their 5.7 engine (maybe same as yours) - and if that's hard to find (as Yamaha hasn't sent a I/O unit this way for a decade or more) - there are plenty of 350 carburetors off of Mercruisers, Volvos, and OMCs, that are already calibrated for that motor. I'd think Chevy supplied pretty much the same engines to all the manufacturers.
     
  7. LMannyR
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    LMannyR Junior Member

    I really have to disagree. ECM engines created are MORE effecient, clean, and powerful engine. I'm not aware of all marine engines made today but the ones I do know, all make ecm controlled engines. There is a good reason why it's so.

    So lets say I rebuild the current block, can't I just pull all the electronics from a similar engine and retrofit? Only snag I find is reprogramming the ECM. I was hoping this was done many times by many people by now. I'll google now...
     
  8. tuantom
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    tuantom Senior Member

    "If you can salvage a complete fuel injection system from a wrecked boat, and the price is right, that'd be an attractive option."


    I agree they are better. If I were buying new, I know I'd go that way. How much money do you want to spend? Is the boat worth it? I don't know. I just think if you have the setup for a carburetor already, it's the fastest, easiest and cheapest way to go.

    My point was - the efficiency gains a boat engine sees (unintended) are not as great as the gains a car would achieve.
     
  9. LMannyR
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    LMannyR Junior Member

    Let me clarify a bit. Can I pull the parts off an auto and bolt it on? Auto engines are just so cheap. Why not use it, keeping safety in mind? The

    Only problem I really see is the Oxygen sensor in the wet exhaust? Are there "dry" exhaust manifolds available for marine use? Obviously I would also have to install a heat exchange unit.
     
  10. gonzo
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    gonzo Senior Member

    Auto engines use a pump on the fuel tank. That would pressurize the line going to the engine. Marine pumps are mounted on the block. That alone makes the whole injection system a problem in a boat.
     
  11. gonzo
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    gonzo Senior Member

    Have you found parts for your engine? I have a new GM350HO with two hours on it that froze and cracked the block.
     
  12. LMannyR
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    LMannyR Junior Member

    I moved away from the engine chapter. My time is concentrated on restoring the the rest of the boat. As was stated above, if the price is right then why not?

    What are you asking and for what specifically?
     
  13. broke_not
    Joined: Jun 2008
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    broke_not Junior Member

    Hi,

    New here....and just wanting some clarification. I know this thread is a bit dated, but I came across it while searching the 'net for similar information.

    Anyway, what I'm wondering is why the in-tank fuel pump would rule out, (or at least make the installation problematic), on an automotive-type EFI engine in a boat application? The reason I ask is that many of the industrial/construction engines I work on every day use automobile-type EFI systems. While it's true that most automobile fuel pumps on such applications are mounted in the tank....not all of them are.

    Many of the same engines we see that come from automobile/light truck manufacturers, and are equipped with in-tank pumps in their normal road-going applications, nix the in-tank pump for their industrial or construction applications.

    On some of our stuff, this pump is used:

    Napa inline EFI pump

    Other use slightly different pumps, but you get the idea. Since the pump is inline, it can be mounted almost anywhere. Closer to the tank is better of course, since electric pumps always "push" better than they "pull". On several of the pieces of equipment, the engine is on the opposite side of the machine as the fuel tank is. Six or seven feet of hose lead from the tank to the pump inlet, and as long as they aren't run completely out of fuel there aren't any issues. On some of the engines, the output pressure to the fuel rail is regulated by a three line combination fuel filter/pressure regulator.

    The pump simply has an inlet line coming from the tank, and an outlet to the filter/regulator. The filter/regulator is also an inline device, so mounting it anywhere is easy to do as well. One line comes into it from the pump, one line out is a return to the tank.....and the third line out is to send fuel at the correct pressure to the fuel rail.

    It seems like this same setup could be easily applied to a marine application.....or am I missing something?
     
  14. gonzo
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    gonzo Senior Member

    The return line would be the first problem on a boat. It is a pressurized line. The feed line is also under pressure, which makes it difficult to make compliant with regulations. Another problem is fuel overheating. Most marine fuel injection systems have a fuel cooling part. Fuel lines have to either be metal or USCG compliant. It can be done, but there are plenty of marine fuel injected systems and engines availble. I think that unless you are doing it as a hobby project it makes no sense to spend the extra time and money. You will also end up with a product that has less value than a standard factory setup.
     

  15. broke_not
    Joined: Jun 2008
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    broke_not Junior Member

    Hmmmm.....I wouldn't think finding rated line would be an issue, it's pretty common stuff nowadays. How do fuel overheating issues arise in a system that constantly pumps the fuel in a loop? Years ago, problems like vapor locking were a constant battle....but having fuel at higher pressures in the lines and constantly moving in a loop did away with all of that.

    I'll admit that I'm not familiar with marine regulations for this stuff, but the industrial stuff I see daily really can't behave all that differently....
     
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