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Discussion Starter #1
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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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.
 

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Discussion Starter #3
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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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?
 

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Discussion Starter #5
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 ?
 

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Discussion Starter #6
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
 

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I'm No Expert
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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
 

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jetboataholic
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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.:)hand
 

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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 ;)
 

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Discussion Starter #12
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
 

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E-7 Sheepdog (ret)
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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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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 :)st) than it would start right back up later.
 

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Discussion Starter #15
yes will look at the breaker in the back

and keyswitch first thing in the morning

thank`s a lot

i appreciate your help a lot guy`s

thank`s
 

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Discussion Starter #16
hi everyone

i have the main circuit breaker in hand but it`s very old and there is nothing i can read on it

can someone tell me what is the amp ?

thank`s
 

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Discussion Starter #18
hi all

just found out that my alternator was producing more than 17 volts

can it be the problem to my stalling engine when hit the gas ?

it will produce more voltage and then maybe stop current for safety on the engine

and waths for the ing .. its just key switch then go to main circuit panel
mallory ingnition protection panel

and wire to electric fuel pump


thank`s
 

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had an alternator that was overpowering one time. it would cause the circuit breaker to pop and that was only 15v. circuit breakers are basically thermal switches. when they get too hot they pop bad contacts or excessive corrosion will creat more heat and when you at 17v to something that suppose to be around 13.0-14.0v you have a problem.

another thing that sounds bad to me (and also increases the load) is that from what i read it seems you have the fuel pump running through the ignition switch? i would change that right away and put in a relay in, that way all the load from the fuel pump is isolated to a much smaller circuit and the ignition switch no longer has to carry that load. high resistance (from corrosion, too small gauge wiring, or just the amount of distance electricity has to travel) can cause a lot of weird intermittant problems, not to mention much more dangerous for overheating and fires. so if i were you that would be the first thing i change along with the alternator. I even have my crane ignition on a relay along with my fuel pump. i hate the thought of that $15 switch at the front of the boat handling everything that make my $6k engine at the back of the boat run.

AP
 

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www.highflowdynamics.com
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Also check for water in the gas (tanks and float bowls).

LO
 
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