stalling at high rpm
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stalling at high rpm

  1. #1

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    Default stalling at high rpm

    Hi everyone

    i will have to tell all the story so someone can give me the good answer

    boat at the begining of the season runs great

    then one day when i returned from the other shore of the lake , i was a great condition lake to try at full throttle the boat , the lake was a mirror

    i was going very fast then , engine make a backfire and stalled

    first i thoutgh that i blowed the engine

    then i try to restart and it start good

    but because i was affraid of brke the engine and not getting home

    i go very slow to make sure that i go home safe

    at home i checked the compression

    210 230 230 230
    230 230 230 210

    its a 454 bbc crank 500hp

    then one nigth want to go whit my girlfriend for a little ride

    start the boat

    go iddle to the lake

    the hit the pedal and after a couple of seconds
    it stalled again at high rpm whit a bacfire

    went back home , look for electric fuel pump

    the magnet were not good

    so change the fuel pump

    holley electric blue

    check ground ..... wire .....

    go for a ride and same thing happen

    i have to mention

    when i put the key switch to ignition i hear the fuel pump

    then start .. the engine runs great at iddle

    when hit the pedal and stall

    the electric fuel pump is stoped at the same time

    then i can hear the fuel pump getting powered again

    can it be a short wire ?

    the fuel pump is suppose to stop at the same time that the engine stall ?

    im asking this because the power to electric fuel pump is suppose to be there even if the engine stalled

    can it be a bad key switch ?

    please help

    thank`s

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  3. #2
    Senior Member 78Eliminator's Avatar
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    There any way you can put a gauge in line with the pump? Sounds like you are running out of fuel when you romp on it. At least this way you can see if your pump is turning off. hope this helps. also your pump should keep running as long as the key os on.

  4. #3

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    yes thank`s i will try

    but to me if the fuel pump stops at the same time that the engine stall

    why is it getting power back 5 seconds after the engine stalled

    is it not suppose to stay under voltage ?

    maybe i`m running out of fuel like your saying

    i will take a look at the fuel regulator and make sure i get around 7 psi

    do you suggest another psi pressure ?


    thank`s

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  6. #4
    Senior Member jetboatperformance's Avatar
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    Eric is the Carburator a Holley vacuum secondary ? and yes your fuel pump will quit if the engine dies IF its rigged thru an oil pressure switch Tom

    PS Where are you writing from?

  7. #5

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    yes it a holley carb but do not know if its a vacuum secondary

    i had many boat before and this is my first jetboat whit problems

    so i do not know about secondary carb but for sure its a holley

    and thanks to let me know that the fuel pump stop even if it suppose to run when its stalled


    maybe a dirty carb ?

  8. #6

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    my fuel pump is connect on the ignition screw on the board

    but no oil pressure trigger ?

    is it somewhere or on the electrical board connection

    oil pressure is very good

    at start is over 80 psi and go down as the motor get high rpm

    maybe go around 40 psi

  9. #7

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    i`m in the montreal area

  10. #8
    I'm No Expert Shaun's Avatar
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    If you have a fuel cut off when there's little or no pressure this could be causing the problem. Maybe at WOT your pressure drops way low or maybe you just have a bad sending unit. I had a bug once that had a electric oil pressure guage and it would get wacked out after a while and would pin the guage for a sec and then go to 0

  11. #9
    jetboataholic HawaiianJet's Avatar
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    Question

    Don't really know if this matters, but what kind of engine is it? Chevy? Ford? Olds? And is it a big block or small block?

    Good luck.
    HJ

    ***FOR SALE*** 1978 19' Full Stringer Hawaiian Molokai Jet Boat w/ Berkeley 12JC-AB and Chevy 440 Tall Deck ***FOR SALE***

    Quote Originally Posted by mako shark mark View Post
    Oh yeah, Forgot to mention that the hull is a special mixture of speedcote, herculiner and rain-x, all blended together- good for another 8 mph top end.

  12. #10
    Senior Member ClassicBoats's Avatar
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    Detonation......................?

  13. #11
    Senior Member propless's Avatar
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    ericchose, If your fuel pumps power is hooked direct to ignition and its ground is direct to ground it should not shut off with the key on. Have you noticed anything else shutting off with the pump (gauges, stereo, etc) ? My first guess (if other things are also shutting off) would be a bad ignition switch, but also look for and check any fuse holders or circuit breakers you can find. Sometimes they get corroded and will have intermittent connections. My second guess (if nothing else is shutting off) would be a bad/intermittent connection to the pump, check (clean and tighten) all your grounds all the way to the battery. Wiring is such fun

  14. #12

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    thank`s for all the reply

    yes i think its a bad ignition switch

    its a chev 454 big block

    but how can i test the switch to see if its bad or not

    i put the key in , turn to ignition whitout starting the engine

    i can hear the fuel pump working

    i shake the ignition to see if it loosing the power

    no result

    is there another way or a way to see if its the key switch whos bad ?

    the way i see the problem is that i loose signal to the pump

    all ground were check and also wire connection changed

    any other thing ?

    thank`s

  15. #13
    E-7 Sheepdog (ret) SmokinLowriderSS's Avatar
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    Check for a circuit breaker back at the engine wiring connection panel at the back of the engine. I had a breaker corroded up just a few weeks ago, would suddenly stall at full power after a few secconds. No backfire, just everything (I do mean, everything, Dash gauges, ignition, ALL non-battery direct power cut off. It would magically re-power a few to 10 secconds later.

    New $8 main circuit breaker and all is solved.

    I then disassembled the breaker for inspection. Severe corosion on the contacts, arcing, very tiny spots actually making contact.
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  16. #14
    Senior Member propless's Avatar
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    If its the ign switch, anything else hooked to ign will shut off with the pump (gauges, stereo, etc) . Don't forget to look for fuses ! The reason I say this is because when I got my last boat someone had used one of those cheapy plastic fuse holders under the dash and it would loose connection when ever it wanted to (killing the boat at the worst times ) than it would start right back up later.

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