contaminated fuel

Bt Doctur

Supreme Mariner
Joined
Aug 29, 2004
Messages
19,413
working on a 6.2 that would not get out of its own way, would only turn 3100 rpm. Cool fuel unit was replaced under warranty but fuel press was pulsating
42-46 psi . Suspecting bad injectors, they were remove and sent out for cleaning. 7 were in poor condition for fuel flow and balance.
cleaned, re-screend, and tested to like new standards, they were installed and the water test went poorly.
No power, stalling, map sensor code, backfiring, etc.
Found the map sensor plug "unplugged" fixed that but the motor would not give a hint of starting. Checked all fuses, connections ,nothing.
Preparing to go home, I bled the fuel pressure from the gauge and found water???????? . primed and did it again, and again found water?????
Remove a Qt of the "fuel"(fuel did appear cloudy) let it stand and did not see a seperation line. Did a second sample the same way, no visable line??????????
Added a Qt of water to the first sample and guess what,NO SEPERATION LINE. Did the same for the second sample, again no line.
What was visable was a 1/16th inch line at the very top of the liquid.
Not to mention this fuel was tested 3 weeks ago by a reputable marina and found no water contamination
So ,if you have a poorly running motor don't just look for a line when you empty the fuel /sep into a clear conrtainer, take a sample and add water to it.
If you dont see a distinct line of separation , what you dumped out of your filter was pure water
 

Bt Doctur

Supreme Mariner
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Aug 29, 2004
Messages
19,413
Well, the engine is running again running like it should.after 41 GALLONS of water were removed from the tank !!!!!!!!!!!!
 

Bondo

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Apr 17, 2002
Messages
71,251
Well, the engine is running again running like it should.after 41 GALLONS of water were removed from the tank !!!!!!!!!!!!

Ayuh,...... That beats the 'ell outa any record amounts I've seen personally,......

My ole tinbarge drove me nuts with water in the fuel, til I figured out the vent hoses were All wrong,....

Fixed quite a few hulls by movin' the fuel vent from the aft side to the transom,..... especially low runnin' hulls,....
 

bruceb58

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Mar 5, 2006
Messages
30,610
Well, the engine is running again running like it should.after 41 GALLONS of water were removed from the tank !!!!!!!!!!!!

So is that from the fuel supplier or did the owner leave the boat out with the cap off or the vent like Bondo said?
 

Bt Doctur

Supreme Mariner
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Aug 29, 2004
Messages
19,413
the water was fresh/rainwater so we checked the cap .A newer type with the fill and vent combined. Noticed there was no O ring for the threads.
Adding one and installing a fuel/water sep filter.
 

Fun Times

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Staff member
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May 16, 2009
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9,198
41 gallons.:eek: Does the boat have a fresh water system to where maybe someone mixed up the fuel and fresh water fill caps...Accidently sticking a water hose in the fuel tank?
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,610
41 gallons.:eek: Does the boat have a fresh water system to where maybe someone mixed up the fuel and fresh water fill caps...Accidently sticking a water hose in the fuel tank?
That seems the most plausible.
 

BRG25

Chief Petty Officer
Joined
Jul 13, 2001
Messages
528
There's no way you could get 41 gallons of water from a missing o-ring. Someone must have filled that baby up with a garden hose.
 
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