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Thread: eng runs than dies

  1. #1
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    Default eng runs than dies

    Anybody got ideas I have a brand new 351w zero hours new plugs,wires,ect.... eng starts up runs for about 3min than dies sounds like its running out of gas it has an electric fuel pump which i had on manual and could hear it running.

  2. #2
    Member DRIFTER_016's Avatar
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    Buy yourself a fuel pressure guage and stick it in the line near the carb.

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    I would put a little gas down the carburetor to see if it keeps running, that will prove you have a fuel problem. I did have a problem with a electric fuel pump, I switched the fuel lines around and fix the problem.

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    Default check list

    We'll assume it's a fuel problem since that's what you picked up on then.

    First the easy fixes

    Fuel valves open?
    clean filters?
    no pinched fuel lines?
    full tank full?

    Now a bit more involved.

    are you carburated or fuel injected?

    Carburated coul be a stuck float.

    Fuel injected.....

    Is the boat filtered to specs? On some fuel injection if you have too many filters, the fuel line pressure is too low to allow the amount of gas needed for the fuel pumps. If you have a return line to your tank, is it obstructed?

    I have a 496 and put a new electrical harness on it. Boat wouldn't start. We checked the fuel pumps, hi and lo pressure. We had fuel going past the low pressure, but not the hi. But when we turned the key on, we could hear the hi side cycle. It was working, but no gas passing. put a new pump on.....same result. Another new pump, same result. Finally, I asked the mechanic working on it if it was possible we had the leads to the pump backwards and it was running backwards. He said "no, the harness only plugs in one way so it's fool proof". More hair pulling and gnashing of teeth. Same result. Finally, I talked him into cutting the two wires to the plug and reversing them. BINGO, the engine started right up and ran like a champ. The plug in had been wired backwards in the factory. I had to pay a mechanic for 10 hours of time for us to figure that out. (we had also spent time seeing if the electronic brain was functioning properly)

    Good luck!

  5. #5
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    I screwed up then I said “I switched the fuel lines”, it was the power wires.

    Sorry

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    Member Rock_skipper's Avatar
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    I had that problem with an outboard, and it was sucking air. Changed tanks and ran fine. Don't know if the same thing applies with an inboard.

  7. #7
    Member AK NIMROD's Avatar
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    ? water in fuel
    is there a water separator filter?
    RETIRED U.S.A.F. CAPT.; LIFETIME MEMBER NRA; LIFETIME MEMBER ALASKA BOWHUNTER ASSOC.
    MASTER BOWHUNTER EDUCATION INSTRUCTOR; MEMBER UNITED BLOOD TRACKERS; POPE & YOUNG MEASURER

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    Default Pick-up Tube Anti-siphon valve

    I had the same exact problem. Is it draining your fuel filter and then dying? I would prime the fuel filter and it would run for a minute or two then die. I took off the fuel filter to find it empty. There is a anti-siphon valve in the top of the tank pick-up tube that keeps the gas from running back into the tank when the engine is shut off. Mine was sticking and not letting the fuel get from the tank to the filter so I would run the filter out. Check that out but it sounds like that might be it.
    Kammer
    22' Seasport

  9. #9
    Member jeff p's Avatar
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    Default fuel

    First if you believe it might be fuel related lets rule out the boats fuel system. If you have access to a remote tank like the one you would use for a small outboard it can be ran off of that to eliminate the boats fuel system.

    You also said you have a electric fuel pump, does the pump use a relay to prime the system, after starting they usually get B+ thru a oil pressure switch circut.

    If you can give us a little more info we can work this out.

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    Default good info "thanks"

    Thanks for the input sounds like alot of good ideas and I will start trying them when I get back from the slope, some more info it had a new filter installed end of last season also you can see fuel in the filter bowl and there is a relay for the fuel that i replaced.

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    Default yea it works

    thanks for the advice on fuel pressure gage it turned out that the fuel pump would turn off after a couple of min becuse its wired to the oil pressure switch and the oil pressure switch was bad and shutting off the fuel pump to save the eng

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    Member DRIFTER_016's Avatar
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    Excellent!!!!!
    Glad it all worked out for you!!!!
    Good to know the motors safety features work.

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    Hi There!
    This is Christopher from Canada!
    Im new in this forum!

    I had the same exact problem. Is it draining your fuel filter and then dying? I would prime the fuel filter and it would run for a minute or two then die. I took off the fuel filter to find it empty. There is a anti-siphon valve in the top of the tank pick-up tube that keeps the gas from running back into the tank when the engine is shut off. Mine was sticking and not letting the fuel get from the tank to the filter so I would run the filter out. Check that out but it sounds like that might be it.

    Thanks!...

  14. #14
    Member jeff p's Avatar
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    Quote Originally Posted by archeryarm View Post
    thanks for the advice on fuel pressure gage it turned out that the fuel pump would turn off after a couple of min becuse its wired to the oil pressure switch and the oil pressure switch was bad and shutting off the fuel pump to save the eng

    I am glad it worked out for you, hope the info helped

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