carb rebuild didn't work what next?

[gberry420]

I have a 93evinrude 120 m.#ve120tletf which has been idling low until it dies or when the shifter is engaged. It also makes a whining noise that sounds like it is coming from the cylinder. My first post on this forum said that whine was coming from a lack of fuel to a cylinder. I rebuilt the carbs. Still runs fine on the hose but dies fast under water. I also took the head gaskets off and found one cylinder that was much cleaner on the cylinder walls than the others(almost gold the others blacker). What should I look at next? I have gone this far and would like to keep learning. Compression on all cylinders checked 120 or better, I know that is weird. Can anyone help?

 

[wilde1j]

Re: carb rebuild didn't work what next?

Did cylinder head and spark plug in the clean one look steam cleaned? If so, you have water intrusion into that hole going on and you need to find where (start with a very careful head gasket and mating surfaces exam).

No clue about the whining noise w/o more info (does the frequency or pitch increase w/ RPM, etc.)

 

[gberry420]

Re: carb rebuild didn't work what next?

thanks for reply Jim. Haven't had a chance to work on boat lately. About the mystery whine. No it doesn't increase with rpms it only happens after the motor dies in water. As soon as the motor dies there is a whine that starts and lasts only a couple of seconds. Happens every time it is under water and dies. Yes that one cylinder does look steam cleaned. What do I look for there...leak in head gasket?

 

[wilde1j]

Re: carb rebuild didn't work what next?

Head gasket leak, exhaust cover leak, crack in cylinder wall, etc. An OEM shop manual would be helpful here. Check heads and block mating surface for flatness

 

[kenmyfam]

Re: carb rebuild didn't work what next?

Post a photo of the spark plug from that cylinder. (business end)

 

[stingertrey]

Re: carb rebuild didn't work what next?

sounds like a leak in the head gasket.. my 5.5 was doing this dying under water.. bc the head gasket was leaking allowing water into the cylinders and putting out the fire

 

[Silvertip]

Re: carb rebuild didn't work what next?

You said the idle is low! What is the idle speed in the water -- not on muffs? If idle speed is indeed lower than factory spec, you need to do a link & sync (yes you need a service manual for this) as that may have been the issue all along.