Fumes and Sparks

Discussion in 'DIY Marinizing' started by Grebbo, May 8, 2006.

  1. Grebbo
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    Grebbo Junior Member

    I’m still puzzled why you are not allowed a return fuel line?
     
  2. Grebbo
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    Grebbo Junior Member

    Hi Ike,

    You will find that the engine in my friends boat is totally automotive, meaning that it came out of 1991 or so Lexus LS400, I know that for a fact as I’m a regular contributor to the “Soarer” web site dedicated to the V8 and twin turbo Lexus Soarer (the Australian version of LS400). other the Etaon supercharger borrowed from a Jaguar its straight from the engine bay of a good old Jap import, no fancy extra marine this or that, just straight auto motor. It runs fine, no problems whatsoever (Lexus motors are famous for their quality and built, absolutely bullet proof!) furthermore, the engine is unopened and runs stock compression!
    I have attached some pics and a link for any one interested, http://www.planetsoarer.com/joel/Joel.htm
     

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  3. gonzo
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    gonzo Senior Member

    A return line can leak fuel into the bilges. Also, when you convert an automotive engine, remember to reprogram the computer and turn the O2 sensor off.
     
  4. Ike
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    Ike Senior Member

    Grebbo, then they must have designed it with the intention in mind of using it for marine purposes, because there are a whole raft of regulations and standards that normal auto applications don't comply with, they go boom. Any way If it works, what the hey!

    Gonzo. The answer is yes and no (hey, I worked for the government, I know how to give an ambiguous answer) Return lines are not prohibited as long as they don't have any pressure in them. The fuel system regs require that fuel lines suck. NO I don't mean that! What I mean is that the fuel is pulled through the line rather than pushed. So most fuel injected engines don't have return lines direct from the engine. They have recirculating systems or a little tank that sits on the engine and then the fuel is returned by gravity feed or a pump that sucks it back to the tank. This is so that if a leak occurs, fuel isn't sprayed all over the inside of the boat. There are ways around this and I hope I'm not revealing trade secrets here. One manufacturer applied to the Coast Guard for a grant of exemption from the regulations. They have a return line and pressurized hose. The fuel pump is in the tank like on most cars. How they got around it is they use a double wall hose. The inner hose has the liquid. The outer hose never has liquid in it unless there is a leak and then sensors detect the pressure drop and shut everything down.

    It's been on the market for about five years and is being reviewed for renewal of the exemption. As far as I know there haven't been any problems with it. One of the requirements though that the CG made was that the fuel system has a sign on it like your TV that says there are no owner serviceable items in this system. Bluntly, you have to take it back to the dealer for service. The hoses and fittings are not sold by anyone but the boat manufacturer.
     
  5. gonzo
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    gonzo Senior Member

    Yes, if you had a pump in the tank sucking the return it would be legal. A problem with automotive systems is that, unlike marine setups, they have no cooling. The returned fuel disipates heat through the walls of the tank. In an enclosed marine tank, the fuel would end up boiling.
     
  6. Poida
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    Poida Senior Member

    Good info about the fuel pumps.
    I thought "what if the fuel pump in my engine fails, split diaghram for example," so I fitted an electric fuel pump at the tank operated from a button on the console. It recommended a return line as there was no pressure sensing device to stop the pump when the max. pressure was reached. So basically it would only be operated in an emergency at which time the engine hatch would be opened making the fuel filter visible to enable me to see the amount of fuel being pumped.

    Also I was unaware of the dangers of the pump at the tank, thanks for the info but I can't see the problems with a return line as it would have an open end at the tank and as such wouldn't pressurise.

    As for heating the fuel, cars seem to have a metal fuel line running along the engine which even in a car can overheat and cause the fuel to vapourise. In my boat it is a rubber fuel line which is only near the engine when it enters the fuel pump and a take off line from the pump away from the engine back to the tank is not going to create that much heat that in my opinion will boil the fuel tank.
     
  7. tom kane
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    tom kane Senior Member

    Hi Ike,New Zealand does not have Recreational Boating Regulations like the USA.. yet thank goodnes because the Regulation standards would be all you would get from the manufacturers,and nothing better that is available.You would be compelled to make the same dangerous mistakes as every one else.A minimum standard could be sensible but not blanket Regulations which take forever for legal procedure to update to present day technology.Try finding Regulations about fuel injection in boats in the USCG Regulations,you would need an expensive Attorney,then the decision would be open to appeal and interpretation by incompetent local USCG representatives.Looking at the USCG reports on accidents and unregistered boats in the USA seems like a loosing battle.
     
  8. Grebbo
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    Grebbo Junior Member

    Ok, so let me get this right, if the fuel pump sucks rather then pushes (creates pressure in the pipe) its better because if there is a leak, the pump will draw in air into the supply line rather then spray fuel everywhere.
    So my next question is, are there any fuel injection pumps that can be mounted on the engine? Instead in the fuel tank? That doesn’t require return line?:?:
    Its seams insane to swap a far superior fuel injection system for an old carby?:confused:
    Also how often are the governing standards in the USCG updated? Its seams that a lot of the regulations might have been written 30 or so years ago and not current as far as technological advances are concerned? :(
     
  9. Ike
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    Ike Senior Member

    Fuel pumps (for gasoline) are required by the regs and by ABYC Standards to be mounted on or within 12 inches of the engine. Yes there are fuel injection pumps mounted on various makers engines.

    You got it. Because the pump is on or near the engine it is then sucking the fuel to the engine and so in theory if a leak develops the negative pressure in the line drops to zero and the leak is minimized. If the pump were at or in the tank the hose would be under pressure and a leak would continue to spray fuel all over. And since it's a spray, it's being nicely mixed with air creating a mix that ignites readily. (actually I've seen the same happen with diesel sprayed on a hot manifold.)

    Hardly any of the major engine manufacturers are making carbureted engines anymore. Oh, you can still get them, and you can still get marine carbs, but like you said, Why? The Hot Boat crowd still likes big 4 barrel carbs though.

    How often are the fed regs updated. Not very &^%** often. Most of the current regs were written in the late 70's and early 80's and have not changed significantly since except for minor editorial changes. Fortunately the fellows who wrote them (not me, but I know all of them) were pretty farsighted and made them very broad, and performance oriented. The exceptions are the fuel and electrical regs which are pretty specific. The only really significant changes has been to navigation lights on rec boats requiring to be certified like the lights on commercial ships.

    To answer your question though, every five years the regs are required to be reviewed by the National Boating Safety Advisory Council (NBSAC, a group made up of people from industry, boating public, surveyors, boating safety groups such as BoatUS and ABYC, and others and appointed by the Pres.) They are supposed to review the regs and make recommendations for changes, additions deletions etc. As you know not much has changed. During the Reagan administration a bunch of regs were deleted. Not much has been added. Any substantive changes (read that; it will cost you money) has to go through a long process that can take anywhere from 18 months to 3 years to become a reg. Some changes never make it because the public comments are totally negative.

    As for the fuel injection standards you can point your finger squarely at the industry for the lack of any action. In 1999 or thereabouts I wrote a letter to ABYC signed by the Chief of Boating Safety telling them that if they would propose a standard the Coast Guard would consider adopting it. (that's the short paraphrase) ABYC formed a subcommittee to devise a standard. It was made up of reps from the major engine manufacturers except one who shall remain nameless. The standard they proposed was so slanted toward a particular design that nothing every got past the proposal stage and the whole thing died aborning. I retired in Oct 2004 and still nothing had been done. So far with one exception the industry has managed to design their engines in compliance with the current regulations. They occassionally asked us if they could do thus and so and we said yea or nay. But for they most part they have done their own thing.

    And for the comment from Tom about minimal regs, that's what Congress passed. The laws says "minumum standards for safety" It also says that any proposed regulation has to be based on "an established need" which means you can't just adopt regs because you think it would be good engineering practice. In fact the Coast Guard is not allowed to use "good engineering practice" as a basis for a standard. Strangely enough many other branches of government can. The EPA uses it all the time and so does OSHA. So you have to show statistics and studies and research and so on to establish that there is a need, and then it can still get shot down if NBSAC and the public don't like it.(or some congressman doesn't like it.)

    Anyway sorry for my rant. Just venting.
     
  10. StianM
    Joined: May 2006
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    Location: Norway

    StianM Senior Member

    Study the curents.
    The curents go from the mexican golf and across the atlatic befour going north just outside the british islands and up to the coust off Norway.
    It did not end up as police officers in boston, but as politicians in Norway :D

    It's alot off talk aout corosion in a automobile aluminium engine in salt water.
    It's a problem I don't understand.
    Are you using salt water in the engines cooling chanels?
    You don't use a heat exstanger by cooling fresh water with salt water?
     
  11. Grebbo
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    Grebbo Junior Member

    Stianm, I think that a lot of the guys don’t use heat exchanges, just pump outside water what ever it may be, straight into their engines, I would not think it would be a problem if your boat is trailer boat and gets flushed regularly or is a fresh water boat, but if it floats in salt water 24/7 then I would imagine that corrosion would be a big problem, and not only for the motor,:(
     
  12. StianM
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    StianM Senior Member

    That kind off worry me :(
    Marine engines has heat exchangers so converting should include one and also use zink in the heat exchanger to maked shure it will have a long and happy life.
    Really sad since used marine and indestriual heat exchangers can be picked up for free if you know where to look.
     
  13. Ike
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    Ike Senior Member

    Tom, re: your comment about New Zealand not having regulations, they're coming. It took me a day or two to sort it out in my head. Too many years, too many people, too many associations. But here's the scoop. In Australia the National Marine Safety Committee is working on standards for rec boats http://www.nmsc.gov.au/. The New Zealand Maritime Safety Agency, http://www.maritimenz.govt.nz/recreation_intro.asp, is sitting in as an observer. So, whatever Australia adopts will probably end up being adopted in New Zealand as well.

    I have talked to so many different agencies over the years I get confused.
    It's a real who's who. Anyway, I can remember sending info to these people on US standards, and I know they've talked to ABYC and NMMA and ISO and all those other alphabet soup organizations. Most of the time they talked to my boss though and it's been a year and a half so exactly where they are at now, I don't know. You would probably have a better handle on that than me.
     
  14. tom kane
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    Location: Hamilton.New Zealand.

    tom kane Senior Member

    Thanks ike,this is good discussion.We know that NZ follows USA an AU in most of our leagal matters,but our NZCG and many boating groups do not want many manditory regulations at present but prefer education.The main purpose of laws seems to be to determine who is to blame when things go wrong so insurance companies do not have to take legal battles to court.
    Federal Requirements and Safety tips for Recreational Boats
    www.uscgboating.org/safety/fedreqs/equ-vent.htm
     

  15. Poida
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    Poida Senior Member

    It would be nice if they stopped making laws.
    All laws do is make life more and more restrictive.
    Not in my lifetime but in the future boating will probably be against the law becuase it is too dangerous.
     
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