Merc 5.7 Horizon MPI problem

[1Moredrift]

On Saturday on our way in from the fishing grounds the motor was ocaisionally missing, and at Higher RPMs it sounded almost as if there was a cough or backfire (but definitely not as loud as a backfire coming from the engine. I took the boat out of gear and revved the engine and it was smooth, but when back in gear I got the ocaisional cough/backfire symptom.<br /><br />The motor is under warranty, but I want to check as much as I can before turning to my dealer. Once it goes to them I am proabably going to loose the boat for a couple of weeks and they always find a way to charge me for some uncovered work.<br /><br />My first guess is water in the fuel.<br /><br />Another thing to point out is that one of the pulley's froze up on this motor and had to be worked loose with some crc-56. Could that have caused the timing to be off? <br /><br />Help!

 

[Bondo]

Re: Merc 5.7 Horizon MPI problem

My first guess is water in the fuel.<br />

Mine Too........<br />Did you Check the Filter ??????<br />Dump it into a container,+ Look for Water.........<br />

Another thing to point out is that one of the pulley's froze up on this motor and had to be worked loose with some crc-56. Could that have caused the timing to be off?

Nope....<br /><br />Sounds like a Classic Fuel Delivery Issue.........

 

[1Moredrift]

Re: Merc 5.7 Horizon MPI problem

I put waterzorb in both tanks on Sunday, but didn't have time to do much else.<br /><br />I'll replace the filter on the water/fuel separator when I get back to the boat on Friday.<br /><br />Thanks for the reply.

 

[tommays]

Re: Merc 5.7 Horizon MPI problem

when you use waterzorb were do you think the water goes it just makes it harder for the separator to remove the water because now its water mixed with a chemical<br /><br />tommays

 

[1Moredrift]

Re: Merc 5.7 Horizon MPI problem

Tommays,<br /><br />Given that I already put the waterzorb in the tanks, what should I do now?

 

[1Moredrift]

Re: Merc 5.7 Horizon MPI problem

Tommays - Any advice?

 

[rodbolt]

Re: Merc 5.7 Horizon MPI problem

flush the engine fuel system and replace the seperator.<br /> it should be against the law to sell water-zorb crap to the marine market. it makes me a lot of money but causes to many headaches. good luck and keep posting

 

[Hog Wild]

Re: Merc 5.7 Horizon MPI problem

If the fuel filter is clean, you might want to just check the timing and timing advance. Only a 2nd thought to the fuel thoughts though