Fuel Cooler or Bad Fuel

[Sadey]

We have a ton of water in our FWD fuel tank. We put 200 gallons from one nozzle into that tank and 400 gallons from a different nozzle into the aft tank at fill up. Suppling and returning to the FWD tank for 12 hours with no issues. In the morning noticed maybe an inch of water in the bottom of the STB racor so that was drained. Stared both motors and the STB motor, the one with the water, stumbled and died. Shut down the other motor, PORT, and noticed the that bowl was completely full of water. Drained all water from the STB racor changed secondary and using the prime pumps filled the racor back up but it was all water. So we have water in the FWD tank for sure, lots. Switched to supply fuel from AFT tank which was fueled at the same time and switched to clean racors. Set return fuel to the forward tank so as not to contaminate the aft tank and fuel was clean for the 5 minutes both motors idled. Further, the 20KW feeds and returns to the aft tank which was run for about 2.5 hours after refueling and it’s racor bowl is clean. So tomorrow we have a polishing company coming to do its thing. The big question is how likely is it bad fuel or fuel cooler? We filled both tanks but the forward was filled first from a different nozzle then the aft but assumed to have come from the same tank. Talked to the marina, they said they check but sell lots of fuel so most likely not thier issue. Unfortunately I was feeding and returning to the same tank, my bad. Thoughts?

 

[SeaEric]

An acquaintance with a 1984 53 Classic - 871ti's had a similar occurrence. It was the fuel cooler.

 

[Freeebird]

An acquaintance with a 1984 53 Classic - 871ti's had a similar occurrence. It was the fuel cooler.

You talking about Chris?

He made that comment when I posted about this situation on my Facebook page.

 

[madhatter1]

Ugg! sory to hear this. Are you in a safe harbor? Reach out to Wayne at Anclote Diesel in Tarpon Springs. He is super busy and short handed but does travel and take care of people. I bet if he can't get to you he knows someone who can.

Also I would bet the fuel cooler. I litterally have never pumped bad diesel. Me? I would taste the water. Then you know.

 

[Captain Ralph]

Years ago we had a similar issue. I just knew we picked up water from a marina in North Jax.

First, no mater what you do, DO NOT ad any snake oil. It turns the water into a snot that haunted us long after the issue was resolved.

You can cheaply bypass the fuel cooler. In a few minutes of running, if you don't see water coming out of a cooler fuel connection, you can remove the fuel cooler from your equation.

I even bypassed our fuel cooler and we kept collecting water in the stern tank long after a fuel polishing and business with another fuel supplier.

I did find the water intrusion; The deck fill sealant had long gone failed aweigh. Deck spray, rain & boat washing water would pass under the deck fill into the bilges. Finally the fuel deck fill hose clamps rested and failed. Then the end of the fuel hose blossomed out capturing any water that would pass thru the failed deck fill sealant, down to the blossomed hose end (big funnel) and into the aft tank.
Took tripled jointed arms to reach it but resealed the deck fill plate, replaced the hose and used real hose clamps.
Since then, looking here first,, I have found flush deck fill O rings to be issues letting water in on other boats.

Good luck, keep an open mind and keep us up.

 

[Sadey]

Thankfully we are docked safely. I tried to taste the fuel but it was hard to tell. We’ve never had any water in our fuel and we run the boat a lot. Checked the deck fill o-rings deck plate, they seem fine. We have about 30 hours of running ahead. Would it be a bad idea to bypass both coolers for that amount of time?

 

[rsmith]

They only cool the returning fuel to the tanks won’t hurt anything. Especially at hull speed. The coolers don’t do a lot anyway. Like I told Randy you will see oil in the exhaust at idle if a cooler is leaking. They almost never go bad.
With all the hurricanes and rain they have had up there I’d bet you picked it up. Even above ground tanks can get water in the vents. I even tape the tank vents on the boat when one of these blasts comes through because the rain can be driven up into the tank.

 

[Sadey]

We did your acid test Scott but couldn’t tell if there was a sheen or not. Little too much wind and current here. I’m hoping it was bad fuel, but it’s a big gamble to cross the golf not knowing for sure.

 

[Fanfare]

That cooler has two separate functions with independent heat exchangers inside the unit. One is the fuel cooler, the other the transmission cooler. There are a bunch of tubes surrounded by raw water being directed to the exhaust showerhead. You would think that the pressures in the transmission line and the fuel line would force these fluids into the exhaust water so you would see a sheen as both are oily. I had a leak in a transmission cooler which turned the oil (same as engine oil) milky. I can't explain how this could happen but somehow, perhaps on shutdown, a vacuum must have occurred and water sucked in. It wouldn't take much. Luckily this happened between the yard and my dock, only about two miles when I found it so no damage other than replacing both coolers.

I don't think bypassing the fuel cooler would be a problem but I am not sure about the transmission cooler. Your large amount of water indicates an intrusion from the new fill up or your deck fill system. It seems to be too much water to come through the cooler. Nevertheless, I would not head across the Gulf without fixing whatever this problem is especially if it could be in both tanks.

I always feed diesel input and return from their respective tank so each is isolated.

 

[Freeebird]

Had the fuel polished today and removed a bunch of water. Virtually nothing in a 1 micron filter.

Running the engines now on separate tanks to isolate the issue. One of the owners at Two Georges Marina called me this afternoon and told me they had dipped their tanks after I alerted them to our issues. He said they dipped the tanks and found no water.

This guy did a great job with polishing the fuel. He definitely knows his stuff, and I would highly recommend him.

 

[Captain Ralph]

I always feed diesel input and return from their respective tank so each is isolated.

Usually SOP to run each tank separate and run the gen-sets from the larger tank.

We run run our gen-sets from the smaller tank. When they fail, we know were bingo and better find a fuel source in 20 hours.

Sadly, my issues were on going during some long runs thru the Tortugas.

 

[Sadey]

I shouldn’t have been running on one tank. I had my reasons in the beginning and got lazy. No more. Going forward everything points to a bad cooler so both will be replaced. Any suggestions on supplier?

 

[rsmith]

The point of having redundant systems is not losing both engines at the same time. I’m still skeptical about the cooler’s. Even after polishing there is a lot of residual water caught in the tank baffles. It will take time to work it all out if ever.

 

[Pascal]

You also have to watch the attitude of the boat when polishing. When I had my tanks cleaned on the hard, the bow was slightly high and a lot of crap and water was left in the aft tank because it has migrated aft away from the access plate.

A few months later I ended up getting 5 gallons of water out of the tank by ballasting the bait forward. I just used a piece of copper pipe with a small electric pump.

 

[Sadey]

One of the things that’s leading us to the fuel coolers is not a drop of water in the aft fuel tank. We filled both tanks from the same pump. 384 gallons in the aft and 200 gallons in the fwd. I put about 75-100 gallons in the fwd before we started filling the aft with the other pump nozzle.
Also the boats attitude is almost level and and we’re on the river with virtually no motion.

 

[cww]

One of the things that’s leading us to the fuel coolers is not a drop of water in the aft fuel tank. We filled both tanks from the same pump. 384 gallons in the aft and 200 gallons in the fwd. I put about 75-100 gallons in the fwd before we started filling the aft with the other pump nozzle.
Also the boats attitude is almost level and and we’re on the river with virtually no motion.

It's the fuel cooler, like I told Randy I went through the exact same thing. If your deck fill seals weren't missing or damaged, the only other place in the system where you can get water in it is the fuel cooler. Randy said he checked the deck fills and the seals were fine, so the problem is a pinhole in whichever fuel cooler is feeding that tank. This happens when (and no offense intended here at all - I made the same mistake) you don't change the zincs in the fuel coolers regularly.

Best advice I can give you is drop whatever you're doing and go to a marine store or truckstop now and get some Biobor and dump the entire jug into that tank. I wish somebody had told me to do that when I first had this problem. Once algae sets in it's a b!tch to get rid of. A year later after replacing both fuel coolers with new (I realized I probably damaged both by not knowing to change the zincs in them so I replaced both), I had to have the fuel polishing people out twice. Once to remove the water, and again to address the algae. I still occasionally get plugged filters from it, I came through the inlet the other day on a plane and it the weather was a little froggy, I lost an engine very shortly thereafter. Plugged filter with dead algae. That's only happening in rough conditions every so often now, I went through like 10 filters in the beginning. Put biobor in there immediately so you don't spent the next year dealing with that problem. The fuel polishers will get most of the water out but there will still be some minor amount, and it doesn't take much for it to grow.

 

[SeaEric]

You talking about Chris?

He made that comment when I posted about this situation on my Facebook page.

No. Someone else.

 

[Sadey]

Thanks Eric. Plan is to pull both coolers and pressure test with two new ones in hand. If they both test good its the fuel so we send the new ones back, if we can and continue to suck water/fuel out. If not we replace both coolers.

It's very odd that the water level in the one tank keeps rising, much slower now, after sucking water until there's none that show on the stick. There is no movement of the boat at all. The sump for the contaminated tank is farthest aft and directly below the float access. This is where we are removing the fuel/water. The boat does sit slightly bow down. Just throwing this out for ideas.

 

[JD5652]

Thanks Eric. Plan is to pull both coolers and pressure test with two new ones in hand. If they both test good its the fuel so we send the new ones back, if we can and continue to suck water/fuel out. If not we replace both coolers.
.

IMO, fuel coolers are relatively cheap, I'd replace no matter the result of the pressure test on the old ones. Understanding the pressure test on old ones is important to confirm source of the water in the fuel.

 

[Fanfare]

My original Detroit fuel coolers on my 6-92TA replacement engines, installed around 1992 or so had their zinc pencils installed on the top of the cooler. While I replaced these annually they always had the lower half inch looking like a mushroom at the tip with the upper part looking new. The tip usually broke off in dust on removal as it was wider than the hole. As Fanfare is stored in brackish water for about half the year I interpreted this as the residual raw water seeking a level in the cooler where most of the zinc's protection was exposed to air instead of conductive and protective water. The small portion in the water was depleted leaving them ineffective. It did take about 15 years for this to degrade the cooler. After one went bad I replaced both with new DD coolers. These now have the zincs on the bottom of the cooler, much more exposed in the water. A little harder to service but probably an improved design. Fingers crossed. Be sure to look for this on replacements.