5.0 efi mercruiser - cranks but wont start !!!

[pabalo888]

Hello there,

2 weeks ago i had this motor running at 4500rpm doing 40knots and running fantastic....

I turn my key from off to on the next weekend, get my audio sound and can here my fuel pump priming....wait for the prime to finish and she just cranks and cranks, normally it take 2 sec for her to fire up.......

Any ideas???

I do not wish to take her to the mechanic, last time the lanyard switch was not fully turned onto run, in which it cost $90 aussie dollars for him to inform me of this.....from reading other posts, some say it is the ECM, oil pressure switch or ignition switch / lanyard......hoping it is something I can fix before I head back to my next month of work !!!

Cheers
From Down Under

Paul

 

[Bt Doctur]

Re: 5.0 efi mercruiser - cranks but wont start !!!

check the coil wire for spark.if no spark ,check the + side of coil for 12v

 

[Fun Times]

Re: 5.0 efi mercruiser - cranks but wont start !!!

Hi there, welcome to iboats! What year engine do you have? Is this an alpha or bravo stern drive?

If it's an alpha drive, Have you moved the shifter to forward, neutral, reverse and back to neutral to see if maybe the shift cable is holding up the shift interrupter switch?

Also have you tried advancing the throttle only to about 1/4 throttle to see if the engine will start? This will allow more air to the engine while testing to see if the idle air control is not working properly.

 

[pabalo888]

Re: 5.0 efi mercruiser - cranks but wont start !!!

check the coil wire for spark.if no spark ,check the + side of coil for 12v

I visited my car mechanic and he gave me a spark tester, I tested and had spark coming through....

 

[pabalo888]

Re: 5.0 efi mercruiser - cranks but wont start !!!

Hi there, welcome to iboats! What year engine do you have? Is this an alpha or bravo stern drive?

If it's an alpha drive, Have you moved the shifter to forward, neutral, reverse and back to neutral to see if maybe the shift cable is holding up the shift interrupter switch?

Also have you tried advancing the throttle only to about 1/4 throttle to see if the engine will start? This will allow more air to the engine while testing to see if the idle air control is not working properly.

Hi, Not sure on the year of make!!!
I have inherited the vessel from my late father

What info I have
The vessel was purchased back in 2003
Alpha 260hp / 330hrs
Serial # OM601083

I have moved the throttle, 1/4, 1/2 & full and she still just cranked & cranked
I did replace the IAC less than 6mths ago

 

[Fun Times]

Re: 5.0 efi mercruiser - cranks but wont start !!!

Your engine serial number is showing you would have had an bravo drive when new. MERCRUISER 5.0L MPI BRAVO. 2003 is about right with that serial number.

Well unfortunately it could be a whole big list of things that could keep it from starting, but just know your engine model is not affected by the oil pressure switch by way of keeping the fuel pump turned off during starting. The ECM controls the fuel pump.

Start by checking fuses at engine and under dash, check/swap/tap on the relays at engine to see if there are any differences, carefully wiggle the main wire harness at the engine with key on and while cranking over, take note of the RPM gauge to see if it is advancing to about 400 rpm while cranking, be sure all 8 spark plug wires and the coil wire is sparking consistently. You will also need to make sure the fuel pressure is advancing to 43 psi at ignition key up and crank.

Few known problems with your engine model would be moisture under the distributor cap due to distributor design, crank shaft sensor.

When was the cap and rotor replaced last if any?

 

[chrome dome]

Re: 5.0 efi mercruiser - cranks but wont start !!!

also check your fuel filter system for water/rust/sediment/blockage etc etc,
how old is the fuel?

 

[pabalo888]

Re: 5.0 efi mercruiser - cranks but wont start !!!

hello there...
I have had rain for the last 4 days and haven't had the opportunity to open the engine bay
Thanks again
Cheers
Paul

 

[pabalo888]

Re: 5.0 efi mercruiser - cranks but wont start !!!

also check your fuel filter system for water/rust/sediment/blockage etc etc,
how old is the fuel?

Hello all,
I have hopefully fixed the problem....inline fuel filter was blocked!!!
I replaced it 2mths ago using genuine part.....
Replaced with CVA filter and she started on the trailer, I will do a water trial today.
Thanks again, I will advise you on the water trial.
I might even replace the tank anyone know of a good stainless steel tank manufacture?
I have 400ltrs, may reduce to 2 x 100ltrs....
Cheers again
Paul

 

[BIGALF]

Re: 5.0 efi mercruiser - cranks but wont start !!!

You might have a screen at the bottom of the fuel pick up tupe that is in the fuel tank. Check that also and make sure the screen is clean.