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Racing Engine

  • August 27, 2012 1:34 AM
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    Message # 1057458
    Anonymous member
    Hi, We're currently in Madagascar where there is a distinct shortage of English speaking mechanics, so I'm hoping someone here may have some ideas.

    Our Volvo MD2040 has developed an interesting quirk - after running for about an hour the revs suddenly shoot up of their own accord. If you put the engine back to neutral then bring it up again it stops - until next time. This mainly happens when we are engine charging in neutral, rarely under load.

    Other misc Volvo hints we have found: be careful with non-Volvo oil filters - we had several instances of catastrophic oil loss which delayed our Indian Ocean crossing and cost a lot to investigate, before we tracked it down to our non-Volvo filters failing under pressure and spewing oil out. Have changed to Volvo ones and, fingers crossed, after several hundred hours of motoring, no problems.

    Also, glow plugs - our all failed and quotes to replace them ranged from 20 pounds to $120 each plus freight to get them to Madagascar. We replaced them with Mazda ones from the local hardware store in Hell-ville for $4 each and they are working fine.

    Thanks,
    Jill
  • August 27, 2012 4:21 AM
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    Reply # 1057541 on 1057458
    Anonymous member
    i would first look at a mechanical fuel pump with a bad diaphragm.  

    good luck,

    rich
  • August 27, 2012 9:30 AM
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    Reply # 1057761 on 1057458
    Anonymous member

    Jill,

             It does sound like fuel starvation. If your fuel tank is above the engine, the fuel should gravity flow (siphon) to the engine even through both primary and secondary filters. If it is not free flowing here are a few things to check:   -plugged fuel filters, plugged fuel tank vent, plugged fuel tank pickup tube.

       If it is not free flowing from the tank try blowing backwards through the fuel line into the tank. If you use compressed air for this first make sure the vent is clear or remove the fill cap.

       If the tank is below the engine Rich may be right about the fuel pump. Disconnect the fuel line after the pump and crank the engine too check fuel output. Close the raw water seacock when doing this so you dont fill the muffler and flood the engine with seawater.

                                                                                 Very much enjoy your writings in Windblown,  Lee
  • August 27, 2012 7:11 PM
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    Reply # 1058113 on 1057458
    Deleted user
    All the suggestions sound reasonable to me.  Some friends had the same problem in Mexico and it turned out to be the injector pump.

    You might try Daryl Eskelund @ eskelundmarine@sbcglobal.net, He is the best Volvo mechanic I've seen.

    Jim
  • August 31, 2012 3:30 AM
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    Reply # 1061471 on 1057458
    Anonymous member
    Thanks for this, guys. We had been suspecting/dreading injector pump, but will investigate fuel starving first. Possible as we are in the throes of dealing with diesel bug - killed but can't clean tanks until we get to South Africa. Just seems odd that it only happens when not under load (so far, touch wood). Motored for 4 hours yesterday with no problem.
  • June 10, 2013 6:41 AM
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    Reply # 1313505 on 1057458
    Anonymous member
    Ok, good news and bad news. The good news is we finally got it sorted in Paraty, Brazil. The bad news is that the South African guy who said it was the injector pump and had it overhauled just cut the tips off the injectors, which we have had to replace here in Brazil where import duty on marine gear runs at 100%! The problem turned out to be worn part in the speed governor, a sort of cone-shaped piece of plastic. The mechanic here was great, as most of the engines here are Volvo MD2030/40 he has had heaps of experience and identified the problem instantly. Just as well, as it was starting to do it when the engine was in gear. Water skiing anyone?