Preview: Marine Diesel Engines, Part 7 – How to Bleed the Fuel Injection System

26 Responses So Far to “Marine Diesel Engines, Part 7 – How to Bleed the Fuel Injection System”

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  David Brown says:

  This was much better than anything I have found on YouTube. Notwithstanding, I was hoping for the approach for the complete NOOB that I am. I noticed the instructor used a remote starter which I will have to use as the companion way steps are the engine room door. The instructor did not include the details of installing and using the remote on the starter motor. I am reluctant to guess my way to installing the remote correctly (safely) and turning the motor over. And, I have a concern with shutting the motor off in case it does start. My YanMar is 2010 and has 700 hours on the clock and is manual shutoff only. Still looking for the complete bleed procedure. I’m more confident now but will research further before continuing. A simple oil/fuel filter change started a few days ago has turned into a project!

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  Brian Walk says:

  Great series. My question is about the diesel fuel that drips out. Is there a danger in a fire it if hits a hot exhaust component, or can there be a backfire or something that ignites it? Thanks

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    Maynard Bray says:

    Hi Brian,
    Although it won’t explode, diesel fuel will burn, for sure, so letting it spill onto a hot exhaust is a no-no. Usually, bleeding takes place on a cold engine that won’t start, so the surfaces aren’t hot. But if that’s not the case and the engine is up to temperature, you need to take more care with spillage and have a fire extinguisher at the ready. Diesel engines have no carburetors, so backfiring can’t occur like it does in a gasoline engine. Use common sense when bleeding your diesel and you should have no problems with fire.

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  john yates says:

  Since the bleeding process yields lots of fuel spilling all over the place, I’ve found that after wiping up with plenty of paper towels, I then spray the entire area with pet (cat) urine cleaner to get rid of that nasty residual diesel smell. John on Indy

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    Jon Bardo says:

    Brake clean is another good product for cleaning engines. JCB

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  Samuel Jobin says:

  Thanks for your videos. It’s this series that got me to sign-in. They are worth a few years of membership alone!

  I have a question though. I changed both my primary and secondary and I’ve bled my diesel line like showed in the video. After doing so, while leaving the marina, the engine started to misbehave. Like if it was about to choke. Then it was coming back, then re-choking, etc etc etc. Could it be that there is still some air left? Having air in the diesel line, would the engine keep going like mine or it would just choke?

  The strange thing is; while doing some test in neutral, I didn’t encounter the problem. It seems to be only when there’s a load on it??

  sam

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    Jon Bardo says:

    Sam,
    Some engines require a longer bleeding cycle than others, seems you have one! Under load the engine requires more fuel and may stumble (the stumble may be more apparent) at this time. The pumps used to do the bleeding may require more strokes due to their small size.
    JCB

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  Ben Zehnder says:

  I watched this video many times this winter and the other day it paid off. My Yanmar 4 cyl. died in the middle of the channel just inside the Chatham cut last Sunday in a hard running tide and heavy boat traffic. I set an anchor, cursed whomever invented large multi engined center consoles, swapped out the fuel filter and bled the filter canister. I had never done this before but it worked just like in the video. The engine started right up. Thank you so much Jon for the video. Thanks also to my future wife for going below, reading a magazine in a rolling boat and never saying a word. Trust like that is intoxicating. One thing I did learn – the engine had lost power momentarily several times in the prior week. I should have pulled the filter at the mooring after the first time. Thanks again Jon..

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    Jon Bardo says:

    Ben,
    Add some Bio-Bore JF to the fuel if you suspect any bio growth. Should this be the case, be sure to change the filters sooner than later!

    JCB

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  David McKay says:

  Wonderful series. These are issues I deal with rarely, but train for regularly. Having a ready resource like these videos is a great refresher and now a regular part of my recurrent, pre-season training. (They’re fun to watch in the winter too!) Thanks to all who participated in their making.

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  John Thompson says:

  Great video on bleeding the diesel fuel system. I have searched You Tube many times and there aren’t any videos regarding this topic as clear and straight forward as this series. One question: what about changing/bleeding the primary Racor fuel filter? Is that just as simple as spinning it off, filling the new filter up with clean fuel and spinning it back on? Does that filter need to be bled? Thanks. JT

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    Jon Bardo says:

    John,
    The primary fuel filter (Racor or other) is located on the suction side of the fuel pump and there for cannot be bled as the engine mounted filter is bled. Some Racor filters have a feeble pump incorporated in the filter housing and may be used to help draw fuel from the tank. The trapped air must be bled out after the Racor filter, usually at the secondary fuel filter bleeding port. Filling the Racor with CLEAN fuel is the usual method. Did I mention to use only Clean fuel? A good practice to follow is to run the engine after changing the Racor befor changing the secondary filter, thereby avoiding problems!! JCB

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  Scott Bailey says:

  Biological growth in a diesel fuel system takes place at the fuel/water interface. Water can come from many places, contaminated fuel from the supplier, leaking fill/vent fittings or condensation in the tank. Prevent ingress of water and one will not have growth/contamination issues.
  Commercial marine fuel tanks are equipped with low point drains to verify fuel condition on a periodic basis. Use of chemicals to kill the bacteria are successful but one must be aware that these dead bugs are now going to settle out in the tank and clog your filters at the very least. Commercial vessel lifeboat fuel tanks are routinely dosed with biocide but the best prevention is to keep the tank full to prevent condensation and fill with clean fuel in the base case.

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    Jon Bardo says:

    Good answer, one added note . Should one have a serious algae problem, please have extra fuel filters on board, especially if the fuel has been treated with a Biocide. The now dead bugs will clog the filters!! JCB

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      David Tew says:

      I wonder whether the Bounty’s tanks had dirty fuel which lead to her filters clogging especially when the tanks were stirred up by the heavy seas.

      The investigation of her sinking revealed frequent filter changes before the main engines quit altogether.

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        Jon Bardo says:

        Right on sailer, my thoughts as well. JCB

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        Jon Bardo says:

        I highly recommend the dual Racor filter system(see Hamilton Marine) using the largest size that space will allow and plenty of spare elements on board. Cleaning fuel tanks and polishing fuel on any boat is also a great plan!! JCB

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          David Tew says:

          Comments on this fuel polishing installation
          ? http://www.cruisingonstrider.us/FOpolishing.htm

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            Jon Bardo says:

            Very good article. What has been a standard practice on tugs and other commercial vessels (the use of water separators, prefiltering all fuel before it gets to the engine filters, pumping fuel to day tanks that are higher than the engines, utilizing dual filtration systems with vacuum and pressure gauges, all in use because diesel fuel was considered to be dirty) is now being utilized on smaller boats with very small engines, without engine rooms but only room for an engine!! I am a strong advocate for any filtration and or polishing systems that can be reasonably applied to small boats. Yes Sir, keep it clean!! JCB

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        Jon Bardo says:

        Circa 1971, my Diesel Class instructor, Bob Soucy, told the class that when the seas got rough, you got seasick and the filters clogged, just tie a lanyard around your neck hooked to a barf can and you can keep right on working. HA!!! We thought that he was kidding, NO JOKE.

        JCB

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  Geoff Hobart says:

  I have been a logging contractor in the north woods for over 35 years, and am all too familiar with the need for clean fuel. What I don’t know about are the biological contaminants (algae growth in diesel fuel) that can create problems. Are there products that successfully treat a contaminated system — can you clean a contaminated tank without removal? Any advice is appreciated. Great videos

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    Jon Bardo says:

    Biobore JF is a product that is used to treat BUGS in diesel fuel. Racor and Power Service also market this product in their fuel supplements.Fuel oil can be cleaned or polished (if you are aYachtsman) by pumping the fuel out of the tank, filtering the fuel, pumping the fuel back into the tank and adding a dose of Biobore JF.The key to avoiding this problem is keeping the water out of the fuel. I suggest installing Racor fuel filter water seperators , cleaning the fuel tanks, and locating the source of the contamination on any Diesel Engine experiencing water and algae problems . Clean fuel works best! Rots of ruck! JCB

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  Doug Simpson says:

  Thanks for this very useful information, it very well could come in handy. Learned several new things.

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  David Tew says:

  I am told that one danger regarding inline fuel filters, even when an engine is winterized, is that they can freeze in deep cold (such as we’ve experienced lately in New England) and the internal fiber element can be damaged or degraded so that they fail to filter. Does anyone know if that’s true?

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    Jon Bardo says:

    I’ve never heard of that scenario taking place, although I have seen many frozen filters and anything is possible. To avoid any such unpleasant event, always drain the water from the Racor on a regular basis and change out the element in the spring. Should the primary filter element become damaged as you have described, the secondary filter will catch any unwanted particles in route to the fuel injection pump. The secondary element may then become prematurely clogged, at which time both elements will hopefully be renewed. Have I mentioned the need for CLEAN fuel!!! ThankYou for your question. JCB.

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  Jim Myers says:

  Excellant as usual, please continue series