runs for a few seconds and stops. PLEASE HELP.

[monterey98]

hi there boaters.

i'm having a new problem with my boat that i can't figure it out.
it's a 5.7 efi mercruiser with a alpha one. monterey 236 montura BR.
after winterized i decide to run on the hose to see if was ok for summer but guess what. didn't ran, i mean, ran for 1 min and stops.
i checked the fuel filter and runs full until stop half full, so i bypass the fuel pump relay bypass the tank and also bypass the fuel filter.
if the filter is full runs when gets half full stop, ok enough of that, boats sitted for 2 weeks, now runs fine with 35psi of fuel pressure, ran on the trailer last week fine and for a water test ride for 10 min fine too (top speed and everything).
today i took to the water again and ran fine for 1 hour, brought back to the house and was ready to flush and guess what, after 5 minutes flushing stopped again and don't want to stay running.
i did tune up last july, last year i used my home made computer/code reader and showed code 12 (o errors)
so, could be the fuel pump? regulator? can you guys give me some help. i'm not ready to pay $110 an hour to the local experts.

thanks guys.

 

[90stingray]

Re: runs for a few seconds and stops. PLEASE HELP.

I always run in the drive after winter layup just to make sure all is well. Cause you don't want to end up stranded. Anywho, 5 mins at idle... then just dies? Have you checked all your connections? All wiring and cannon plugs need to be clean and tight. All grounds clean and tight. When it dies, use a test light to see if you have lost power to anything. Check the ignition switch and safety switch all for clean connections and proper operation. Hope this gets you going...

 

[monterey98]

Re: runs for a few seconds and stops. PLEASE HELP.

hey 90stingray

i already checked all of those, one thing that i forgot to check was if sparks ends or fuel? but im pretty sure when the filter/separator get half full than when it dies.

i still need more suggestions.

thanks

 

[Don S]

Re: runs for a few seconds and stops. PLEASE HELP.

Put on a new filter, sounds like you have had the old one off a few times seeing how much fuel is in it. That's a good way to end up with a leaky filter gasket.
Then disconnect the inlet hose from the fuel tank and the engine filter, and hook up a remote fuel tank (outboard tank) with known good hose on it and see if it keeps running.

 

[twostroke87]

Re: runs for a few seconds and stops. PLEASE HELP.

I'm interested to hear about your homemade computer code reader...

 

[monterey98]

Re: runs for a few seconds and stops. PLEASE HELP.

hi don.

thanks for replying but i already did that. the filter im running right now it's less then 3days new, i put grease and fill it up and put it back, if it's full runs fine until gets half full with the boat tank of external tank, doesn't matter.
as i learned i think theses fuel pump works only when primed right? but anyways important thing to say is when the fuel filter it's full runs normal for few minutes.

twostroke87
i found a thread some where that shows how to make a code reader with a paper clip and a led light, when you hook up it blinks, mine showed code 12 = o errors. funny huh?


what else guys? thanks

 

[twostroke87]

Re: runs for a few seconds and stops. PLEASE HELP.

Run the engine until the problem occurs, hook up a portable tank, with an outboard style gas pump ball in the line.

Pump the ball and see if you can either, get it to stay running, or start after it stalls.

Also try to install the ball in between the boats fuel tank and the fuel pump. Start pumping it by hand when it starts to die.

If the problem occurs both on your portable tank and the boats tank it sounds like you def have a fuel pump issue.

mercury verado 4 stroke outboards use a similar pump to pull from the tank, and have issues all the time with working/not working.

Also, that fuel pump should be able to pull gasoline from a tank as far as 30 feet away within a few cycles.

Hook the fuel pump with a portable tank, make sure the tank isn't above the engine (you don't want a syphon to screw up your diagnostics, by gravity feeding the pump)

Power up the fuel pump with the key or manually (its just a DC pump, one wire to ground, one to positive) see how long it takes to draw the fuel, it should be instantaneous. If it doesn't have issues pulling immediatly, then get another gas line and run it back into your boats tank. Stand there and hold it so you can see the flow, and let it continuously run fuel from your boats tank back into your tank fill.

Watch to see if there are any issues with how long it pumps, gets weak, has gaps of air. etc. It should be a steady stream with no gaps start to finish

 

[twostroke87]

Re: runs for a few seconds and stops. PLEASE HELP.

just out of curiosity....if your installing the filter empty...try installing it fully primed with gas, and see if the problem keeps happening then.

 

[monterey98]

Re: runs for a few seconds and stops. PLEASE HELP.

i'm installing the filter full, and after that when i crank runs like a champ for a minute or so and then stops, after stops i remove the filter and i see is only half full, i don't know if i got a weak pump or whatever.

my anti syphon is working fine because i installed a ball/prime pump and fuel flows normal/easy. so i eliminate my tank and syphon.

i also installed a separate tank above the engine level, because i tought the fuel could flow easily after first "suck".

the only thing i can do now is get a spare car pump for chevy v8 i have here and try to install in line between the boat tank and the filter to see if will solve my issue, i just don't know how much pressure that pump will push and also if will work or if the regulator will handle.

i'm still lost.

 

[monterey98]

after tune-up and many testing, bot runs for few minutes and dies.

after tune-up and many testing, bot runs for few minutes and dies.

my engine serial number is 0L025412, mercruiser 5.7 efi, basically whats doing now is, i have to pull the filter out and fill it up so i can get going, and the engine will run for 2 minutes and dies, when i take the filter out it's half full, i heard it's supposed to be full all the time.

i already bypassed the tank, the filter and all even took the gas hose out of the throttle body and there is no gas there.

i already used an extra/external tank and nothing. use a ball primer pump and gas come freely from the factory tank.

there is spark when it dies.

it runs sometime, like a month ago i took the a water test and ran for 30 minutes, when i got back in the house for flush died.

fuel pressure read 35 psi when ran fine.

is it the pump bad? fuel pressure regulator? i dont see any other solution.
some people say the coil or the distributor module.

some help please.

thanks

 

[Don S]

Re: after tune-up and many testing, bot runs for few minutes and dies.

Re: after tune-up and many testing, bot runs for few minutes and dies.

I have merged your new post to your old one. It's still the same problem, so you need to continue on, otherwise we all have to start over. Now we know what is going on.

Have you actually done any vacuum tests on the tank side of the fuel pump to see if the pump is actually pulling any? If it doesn't create a vacuum when run, it won't pull fuel up to it.
A possible air leak in the fuel system before the pump.

 

[monterey98]

Re: after tune-up and many testing, bot runs for few minutes and dies.

Re: after tune-up and many testing, bot runs for few minutes and dies.

well. thanks for bring my question back to life

i didn't do it any leak test, i actually dont know how to do it, and got no tools. is it easy?
let me know how to do it, we about to find out.
maybe the pump still good and don't need to change.

thanks

 

[monterey98]

Re: after tune-up and many testing, bot runs for few minutes and dies.

Re: after tune-up and many testing, bot runs for few minutes and dies.

nobody ? any help?