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  1. #1

    Default Volvo Penta 5.0GL fuel system

    Hello,

    I have a Volvo Penta 5.0GL. It quit all of a sudden one day, ran a little the next and had to be towed back to slip. No fuel was getting to the carburator. I looked at a few previous posts regarding fuel pump relay.

    Terminal 30 is getting power, but when I jumpered 30 and 87, the pump did not work. Thinking it was the pump, I replaced it. It still does not work when 30 and 87 are jumped.

    Any help you can provide would be appreciated....thanks in advance.

  2. #2
    Chief Petty Officer
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    Default Re: Volvo Penta 5.0GL fuel system

    I cant recall the terminal numbers, are those direct power to pump (outside side of relay)?
    If so then the pump is bad. Don S posted links to the factory manual here I think. If not let me know, I have OEM fuel system manual and can look with diagram for you.

  3. #3

    Default Re: Volvo Penta 5.0GL fuel system

    Thanks for the reply. I now have successfully got the pump working.

    The problem now is that the pump works, but it still doesn't pull and gas from the tank. The filter is new. I removed the gas line going into the filter/pump and blew into the line. It seems like the other end of the line is plugged since I couldn't get any air to move through it.

    Should I be able to blow air through it? I tried to take the fittings off the gas tank, but can't seem to move them at all. Any tricks? Am I on the right track?

    Thanks again.

  4. #4
    Honorary Moderator Emeritus Don S's Avatar
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    Default Re: Volvo Penta 5.0GL fuel system

    I removed the gas line going into the filter/pump and blew into the line. It seems like the other end of the line is plugged since I couldn't get any air to move through it.
    That is because of the antisiphon valve in the top of the gas tank fitting (Looks like a hose barb). It's a spring loaded check valve that prevents a siphon should a line break below the fuel level.
    You could have an air leak between the engine filter and the tank, or the pickup in the tank could be plugged. Or the pump could be bad.
    Get a remote fuel tank (outboard tank) and hook it up to the engine fuel filter fitting. Then prime the system and see if the engine will start and run. DO NOT pump the outboard primer bulb while the engine is running. The pump will overpressureize the carb if it's working correctly.
    Don S.


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  5. #5
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    Default Re: Volvo Penta 5.0GL fuel system

    Check it for leaks , if there are no leaks then sounds like anti siphon valve is stuck shut. You can remove it altogether I believe, or clean it and re-install.

  6. #6
    Honorary Moderator Emeritus Don S's Avatar
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    Default Re: Volvo Penta 5.0GL fuel system

    Quote Originally Posted by mikeneal View Post
    Check it for leaks , if there are no leaks then sounds like anti siphon valve is stuck shut. You can remove it altogether I believe, or clean it and re-install.

    Sure, remove it altogether ......... It's like removing the safety from your hand gun, sure you can, but do you really want to ???????
    Don S.


    Please, no PM's (Private Messages) regarding boat/engine problems.
    That is what the forums are for.
    Only forum/moderator issues will be answered in PM's.

  7. #7
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    Default Re: Volvo Penta 5.0GL fuel system

    IMO hand gun safety is slightly different then a anti siphon valve. When did they start to add anti siphon valves to boat tanks tanks? Not exactly same risk mitigation. I didn't tell him to use automotive ignition part.
    Quote Originally Posted by Don S View Post
    Sure, remove it altogether ......... It's like removing the safety from your hand gun, sure you can, but do you really want to ???????

  8. #8
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    Default Re: Volvo Penta 5.0GL fuel system

    Quote Originally Posted by mikeneal View Post
    I didn't tell him to use automotive ignition part.
    but you may as well have

    the anti-siphon valve is a safety device, to prevent fuel from siphoning out of the tank due to a fuel line rupture possibly causing a major fuel spill

    they have been installed on boats for a long time, if no anti-siphon valve is in place, there should at least be a shut-off valve somewhere in line before the pump

    clean an anti siphon valve?? no, replace it if it doesn't work - they're cheap

  9. #9
    Honorary Moderator Emeritus Don S's Avatar
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    Default Re: Volvo Penta 5.0GL fuel system

    One of the neat things about forums is the chance for people to post their opinions on any subject, and they don't even have to know anything about what they are talking about. The bad thing, the ones asking the questions, have no idea if the person answering a question is right or wrong. Kind of scary, isn't it.
    Don S.


    Please, no PM's (Private Messages) regarding boat/engine problems.
    That is what the forums are for.
    Only forum/moderator issues will be answered in PM's.

  10. #10
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    Default Re: Volvo Penta 5.0GL fuel system

    I should have be more clear in my response. I meant remove it and see if it solves issue. Not my intent to leave it out altogether for forever. I wouldn't use a auto starter (or ignition) even for a second to "troubleshoot" a problem but I would take the A-S valve out and test boat. I admit, I should have be clearer and it was a bad idea to suggest he break USCG rules, I honestly didn't realize the A-S was USCG reg. Guess that's why the personal attack about "not knowing what I am talking about". I was a auto tech for a while when younger then went back to school to get a mechanical engineering degree. I have built everything from 11 second street driven NA Volkswagens to automatic transmissions and designed stuff that lives is on the International Space Station, I am not a complete doof. (part doof maybe.... :-) ) I enjoy this site and have learned a ton about boating in my time here and I try to contribute back when I can. I assure you, was not my intent to spread mis information. Don, I suppose it is winter there? You seem to be grumpy (er) these days, or maybe I caught you on a bad day.

  11. #11

    Default Re: Volvo Penta 5.0GL fuel system

    Thanks for everyone's help. I replaced the anti siphon valve and now it works fine. I had no idea there was such a valve....

    Thanks again,
    Barry

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