AzimuthCapt
New member
Hey Folks,
First post here.
I'm delivering a 120' supply vessel from Louisiana to California. Main engines are giving me some serious trouble... Won't reach max RPM (or even close) and lots of smoke. Here's the details and backstory.
Two 16V92 Detroits (Non turbo)
On sea trial, noted max RPM under load was 1650. Owner explained he had a mechanic set the governor to limit it to that to avoid throttle monkeys "burning too much fuel".
20 hours out from Louisiana, we noticed increased black smoke from the mains and we began losing some RPM. Down from 1650 to 1600... A few hours later another 50 lost.
Long story short, about 48 hours out we were down to about 1200 Port and 1400 STBD. We started getting water out of the racor bowls and fuel trap, and then it turned into a pink water+diesel milkshake.
Some looking around revealed that the tank vents on the main deck were substantially shorter than they could have been. Heavy seas were managing to splash upwards into the vent, past the float ball, and down into the tank.
At this point we decided to head for Belize to make repairs but passing Cozumel Mexico the port main quit completely. So we limped back to Cozumel and anchored. As soon as the anchor hit the bottom, the STBD main died too. Neither would restart.
So in summary:
What happened...
- Engines ran decently on sea trial
- Seawater got into the tanks while running and became emulsified with the diesel
- Engines ran on this mixture for about 72 hours before dying
- Lots of black smoke
- Engines never overheated during this time
What we then did...
- Moved the watery fuel to another tank
- Cleaned the other tank and filled with clean fuel
- Flushed the entire fuel system
- Changed all fuel filters
-Replaced ALL the injectors with "new" interstate mcbee injectors
-Ran the rack
...after this, the engines would start again but now had an immense amount of white diesel smoke at idle (even once you to tempt/after running). We ran another sea trial with throttles pushed to the dash.
- We had more black smoke than before
- Port engine would not go over 1370 RPM and acceleration past 850 RPM took about 5 minutes
- STBD engine would give 1650 RPM with OK acceleration but was smoking
- Even after hard running, heavy white smoke continued at idle (though not at running speeds)
- EGT temps read at each manifold with a temp gun varied between 360-700° F
- Both engines would rev to 1850 RPM with no load (out of gear) and smoke was reduced during this
After the sea trial we anchored and did some more tests...
- Pulled valve covers and "activated" each injector individual by hand while idling. Same have the good "Thump thump thump" sound, others barely changed the idle, and some made no change at all.
-Moved some of the injectors around, swapping one that had made the good "thump thump thump" for one that had no change on the idle. We found that the firing/not firing symptoms stayed with the cylinder and didn't follow the injector.
-Pulled some inspection covers. Some pistons were a little wet on top. Rings seemed to be free.
So at our wits end, we flew out a mechanic. He...
- Reran the rack
- Adjusted the valve lash
- Rechecked piston rings
- Pulled off the exhaust manifold on one bank and ran it momentarily, confirmed that at least 2 pistons weren't firing
- Removed one of the injectors that sounded faulty and triggered it with a pry bar in the vise. To the naked eye, spray seemed good
Another sea trial. Same results.
Mechanics conclusion:
Low compression, valves burnt or chocked up with deposits. (My additional theory is that the salt water would have precipitated a LOT of salt crystals which could have clogged up the works in addition to stopping thermal transfer maybe?)
So now we are limping to Belize and expecting to send the heads off to the machine shop.
Anyone have any ideas before I spend all this time and money doing this? I'd love a miracle fix!
Thanks!
Cody
First post here.
I'm delivering a 120' supply vessel from Louisiana to California. Main engines are giving me some serious trouble... Won't reach max RPM (or even close) and lots of smoke. Here's the details and backstory.
Two 16V92 Detroits (Non turbo)
On sea trial, noted max RPM under load was 1650. Owner explained he had a mechanic set the governor to limit it to that to avoid throttle monkeys "burning too much fuel".
20 hours out from Louisiana, we noticed increased black smoke from the mains and we began losing some RPM. Down from 1650 to 1600... A few hours later another 50 lost.
Long story short, about 48 hours out we were down to about 1200 Port and 1400 STBD. We started getting water out of the racor bowls and fuel trap, and then it turned into a pink water+diesel milkshake.
Some looking around revealed that the tank vents on the main deck were substantially shorter than they could have been. Heavy seas were managing to splash upwards into the vent, past the float ball, and down into the tank.
At this point we decided to head for Belize to make repairs but passing Cozumel Mexico the port main quit completely. So we limped back to Cozumel and anchored. As soon as the anchor hit the bottom, the STBD main died too. Neither would restart.
So in summary:
What happened...
- Engines ran decently on sea trial
- Seawater got into the tanks while running and became emulsified with the diesel
- Engines ran on this mixture for about 72 hours before dying
- Lots of black smoke
- Engines never overheated during this time
What we then did...
- Moved the watery fuel to another tank
- Cleaned the other tank and filled with clean fuel
- Flushed the entire fuel system
- Changed all fuel filters
-Replaced ALL the injectors with "new" interstate mcbee injectors
-Ran the rack
...after this, the engines would start again but now had an immense amount of white diesel smoke at idle (even once you to tempt/after running). We ran another sea trial with throttles pushed to the dash.
- We had more black smoke than before
- Port engine would not go over 1370 RPM and acceleration past 850 RPM took about 5 minutes
- STBD engine would give 1650 RPM with OK acceleration but was smoking
- Even after hard running, heavy white smoke continued at idle (though not at running speeds)
- EGT temps read at each manifold with a temp gun varied between 360-700° F
- Both engines would rev to 1850 RPM with no load (out of gear) and smoke was reduced during this
After the sea trial we anchored and did some more tests...
- Pulled valve covers and "activated" each injector individual by hand while idling. Same have the good "Thump thump thump" sound, others barely changed the idle, and some made no change at all.
-Moved some of the injectors around, swapping one that had made the good "thump thump thump" for one that had no change on the idle. We found that the firing/not firing symptoms stayed with the cylinder and didn't follow the injector.
-Pulled some inspection covers. Some pistons were a little wet on top. Rings seemed to be free.
So at our wits end, we flew out a mechanic. He...
- Reran the rack
- Adjusted the valve lash
- Rechecked piston rings
- Pulled off the exhaust manifold on one bank and ran it momentarily, confirmed that at least 2 pistons weren't firing
- Removed one of the injectors that sounded faulty and triggered it with a pry bar in the vise. To the naked eye, spray seemed good
Another sea trial. Same results.
Mechanics conclusion:
Low compression, valves burnt or chocked up with deposits. (My additional theory is that the salt water would have precipitated a LOT of salt crystals which could have clogged up the works in addition to stopping thermal transfer maybe?)
So now we are limping to Belize and expecting to send the heads off to the machine shop.
Anyone have any ideas before I spend all this time and money doing this? I'd love a miracle fix!
Thanks!
Cody