Mercruiser 5,7 EFI smoke !

[schjoth]

Hi -
I have still to find out what is wrong with my engine. I hope some of you guys i able to help me.
The engine runs great idel/wot - no problem,the problem is the masive black smoke that occurs at startup - keeps smoking for a long time.
The problem seems to be when the boat is in the water and not on land how come
Sensors are within range (comp. tested )

 

[guyjg]

problem is the masive black smoke that occurs at startup - keeps smoking for a long time.

It's running rich. What year engine? Is it throttle body EFI or port injected EFI?

 

[schjoth]

GUYJG - year 1999 its has a TBI unit with 2 injectors -

 

[bertg]

If it has an engine coolant temperature sensor, that's what I would check out first.
Bert

 

[schjoth]

Sensors are within range (comp. tested )

 

[guyjg]

Is the fuel pump running continuously? Yes? Check the relay to it. Also check the fuel pressure ; item 16.

shttp://www.mercruiserparts.com/Show_Pictures3.aspdnbr=80950099&ivar=images/COMMON/14156.png&inbr=4856&bnbr=130&bdesc=Throttle+Bodyensor.

 

[schjoth]

GUYJG - no the pump primes and then stops - pressure is 25 psi.

 

[guyjg]

Well, something is causing it to flood at startup. Look on top of the throttle plates when it starts. If you see a puddle of fuel there then I would think one or both the injectors are bad. If fuel is dribbling out of the injector(s) then that's the problem. They may just be extremely dirty or worn out.