Water in diesel issue in a 3988-gctid401939

[Guest]

Two weeks of hell continues while I should be OTW to Desolation Sound

Very long and frustrating story but here is the latest info. Got major amount of water in both fuel tanks. It was either vandalism or bad diesel from the fuel dock I bought the last 400 liters from.

Polished all fuel....didn't help.

Pumped ALL ~300 gallons out (into barrels) and refilled with new diesel.

I have both engines drawing and returning to the same tank. Sea trial shook up tanks and port engine stalled again. Racor and downstream filters and flo-scan homoginizers were 1/2 full of water again. I emptied and refilled them with diesel and sat and watched Racor bowls as we idled around the bay.

The starboard racor has NO water in it and it is running fine. The port racor filled up so fast with water it overwhelmed the racor and stalled the engine again. I repeaded the filter process and sat in the engine room with the port engine shut off as we idled around on the starboard only. The port racor had water constantly dropping into the bottom of the bowl as I kept opening the valve to empty it (while not running the engine) and this continued for almost an hour as we cruised around on the starboard engine.I finally gave up.

Has anyone seen the inside of a 3988 fuel tank? Is it possible that the bottom of the port pickup is lower in the than the starboard pickup inside the tank? Are there baffles in the bottom of the tanks that would hold water in the rear (pick up) section of the tank after pumping the rest basically dry through the sender hole?

Is there ANY other place within the fuel system where water could get into it as described above.

Frustrated and perplexed!!

Deman

[ksanders]

years ago a boatyard owned by a meth head poured RV antifreeze into one of my tanks.

After pumping the tank dry and refilling it, I sat in the engine spaces and dumped filters, and changed out filters untill I got it all out.

It took all day.

Just be patient, keep a close eye on the bowl, and keep dumping it.

Its frusterating but you'll eventually get there.

[The_Other_Gary]

Buy a vacuum oil change pump, the white translucent kind.

Remove the fuel guage sending unit, small hatch under the corner cushion of the settee

Put the biggest wand down into the stern corners of the tank

Pump several times to start a vacuum, you will be amazed at what dirt and water

you will collect. You may have to do this several times but you can pour the top

clean fuel back in the tank and pump again.

Far cheaper than buying a case of filters and you can see the results.

Polishing fuel does not get this stuff unless the polisher does this to the tank.

most polishers hook up to the fuel lines and never address the bottom inch or so

of the tank below the pickup tube.

[smitty477]

"The Other Gary

Buy a vacuum oil change pump, the white translucent kind."

Yup - exactly what Gary sad is what we did when we had ths issues.

We used our oil pump (vane puppy) and copper sections of icemaker tube which was flexible & bendable but would hold a shape for reaching interesting areas. That and a really good flashlight helped us get most all of the water out by pumping and decanting into 5 gallon fuel pails.

Take your time and be safe.

Hope this helps

[iceclimber]

The Other Gary wrote:
Buy a vacuum oil change pump, the white translucent kind.

Remove the fuel guage sending unit, small hatch under the corner cushion of the settee

Put the biggest wand down into the stern corners of the tank

Pump several times to start a vacuum, you will be amazed at what dirt and water

you will collect. You may have to do this several times but you can pour the top

clean fuel back in the tank and pump again.

Far cheaper than buying a case of filters and you can see the results.

Polishing fuel does not get this stuff unless the polisher does this to the tank.

most polishers hook up to the fuel lines and never address the bottom inch or so

of the tank below the pickup tube.

+1 on this kind of pump. They are the shizzle. The one thing I will add is make sure you get the reversible kind - MV7201. That way you just pump the crud right back out into waste containers. They make a model that you hook up to compressed air, I prefer the manual pump.

http://www.mityvac.com/pages/products_fee.asp

[Guest]

Latest info.

I actually had the use of an real fuel polishing machine and assumed I had missed some of the water after the polish, then the empty and refill with new fuel due to lower baffles or perhaps the hose has curled upwards and missed some water.

I was drawing the diesel out through the fuel sender hole. After water showed up during the latest sea trial I decided to be extremely thorough with the next pumping scenario.

This morning I attached the in line to a dowel with zip ties to ensure I had the end of the line on the exact bottom of the tank and was able to get right to the back of the tanks due to a hole on the top of the baffle closest to the rear of sender hole. I pumped until the large glass bowl on the Racor water separator part of the polisher filled with water then shut off the pump and drained the water. I repeated this process until no more water was visible. I extracted another 3 to 4 gallons from each tank.

Off to the new sea trial thinking I had finally beat the water beast. Ran great for about 5 minutes then the starboard engine started repeating the RPM loss I had seen so many times in the last two weeks. Sure enough the racor was filling with water again. DAMN!!! I switched the starboard engine to the port fuel tank assuming I must have missed some water. 5 minutes later the port engine racor started to fill with water and finally stalled when we couldn't keep ahead of it by draining the racor.

I limped back in on the starboard engine and dipped the tanks with a water sensor gel on the bottom of the dowel and found another inch of (salt) water in each tank. DAMN DAMN DAMN! NO WAY could I have missed that much water so I started looking more closely at the fuel lines and noticed that 4 lines entered or exited a large plate area on the lower port side of each engine where the oil pressure sender is located.

I snagged my over worked diesel mechanic on his way past my boat and suggested that spot must be where I was picking up the raw water in my fuel. He looked at me like I was crazy and hopped aboard to take a quick look and then quickly pointed to the large pipe running diagonally in front of the spot I was talking about and said "FUEL COOLER" The fuel line attaches to both ends of this raw water pipe and obviously had a line running lengthwise through the inside of it to cool the return diesel. We are assuming it has corroded inside the pipe which allows raw water to return to the tank. I will pressure test it tomorrow and replace it if it proves faulty.

I write this novel hoping to save others from the nightmare I have gone through trying to figure this out for the last 16 days. I personally never thought there could be a spot where raw water and fuel could be in contact with each other on the engines ( along with many others I talked with on the matter)...looks like I was wrong ...sigh

[smitty477]

Great catch but now a new project.

This is one of the weak spot on the Cummins B series engines and many folks believe that you do not need those fuel coolers on the engiines at all.

Perhaps browse through a long standing Cumins service center at Tony Athens site sbmar.com and consider what you read in his TSB's.

Or beter yet since he has serviced and improved hundreds of these engines call him and talk over what your next steps might be now.

Another good source for valuable information woudl be boatdiesel.com as it is only $25 for eveything.

Hope this helps

[Guest]

Echo the comments on using Tony Athens at www.sbmar.com , he talks often about removing the fuel cooler.

Please post your results on the pressure test. The way those things look on the inside, I imagine if it is the cooler itself you will be replacing or removing all together. I can't imagine them coroding much but give us an update either way.

Good luck.

[Guest]

This vacuum pump you guys are talking about looks like it might be something we might want to use on an annual basis.

Would you guys buy one for just maintenance to prevent buildups of the crap in the bottom of the tanks?

Or are they kinda spendy for just that.

[smitty477]

"This vacuum pump you guys are talking about looks like it might be something we might want to use on an annual basis.

Would you guys buy one for just maintenance to prevent buildups of the crap in the bottom of the tanks?"

IMO - these are not spendy vacuumn pumps and are great for removing oil, trans fluiid and the like.

Again IMO the need to clean tanks is not something you would want to plan for.

If you get them clean, use good fuel, have good "O" rings on the fill caps, and change fuel filters you should be in good shape.

We did add vacuumn gages on the fuel filters to identify when they are ready for changes.

Hope this helps

[Guest]

I will echo what others are saying...I have removed my fuel coolers afew years ago and thus eliminating this very worry. There is tons of experience and good advise on boatdiesel.com. This is a VERY simple change and imo you simply do not need them, unless you operate at max power for extended time periods, which I do not. With fuel coolers, the somewhat cooler fuel simply enables the theoretical max rated HP of the engine, and I guess that means something to the engine manufacturer.

Cheers Rick

[WhiteRockMike]

Wow, I'm very sorry Deman for what you must have been going through, but do very much appreciate the info - I wouldn't have suspected the fuel coolers, but now I sure will if it ever happens to me. I have read Tony Athens' article about removing them, but seem to recall that one of the main reasons was to provide better access to that section of the engine, including raw water pump access. I now see another very good reason!

Our fuel up on the West Coast stays pretty cool anyway, so they are of even more limited value here.

Good luck with removing them (after confirming they indeed are the problem) and hope you get back on the water soon!

[Guest]

The starboard cooler was indeed the culprit. I have ordered 2 new ones from Tony (they are only $225 each delivered to Western Canada)

I have read his info about not needing them and am going to bypass that cooler until parts show up. He did mention that without the coolers your salon temp could rise considerably during a long trip as the tanks could reach 140 deg F

[Guest]

Turns out both coolers had issues. The port cooler was not in as bad shape as the starboard one but it was also leaking.a little bit. I have installed bypass hoses on both engines which has cured the problem completely. The hoses cost me $30 each to have made up by my local hydraulic guy and I am going to run the boat with them installed to see if it makes any difference before I install the new coolers.

I will keep you all informed as to how it turns out.

I think I have blown over $3000 by the time I finally figured out the actual problem and also missed my annual trip to Desolation Sound

Hopefully this info helps others that runs into similar issues with their fuel coolers. It should also be a warning to be prepared in case yours fail. My boat is now 14 years old with roughly 1600 hours on the engines and I don't believe there is any maintenance one can do to stop this from happening. Replacing or bypassing them before they fail seems like the only solution