Water in Racors

missnmountains

missnmountains

Active Member
Dec 12, 2007
563
Florida
Boat Info
2008 58 Sedan Bridge
Engines
900 Man
On our way to Bimini last week, the WIF alarms went off on both engines (540 Cummins) within about 15 minutes of each other. Sorry we did not make it Mike and Randy. We did make lemonade out of lemons in Key Largo and then down to Key West.

We had a mechanic visit us in Key Largo. There was only about an inch of water in the bottom of each bowl and all four filters were good as new. He had to empty each bowl to get the water out and refill them with about 3 quarts of fuel each. As far as I am concerned it is a dumb design to not allow for easy service and having the alarm sensors on the bottom of the bowl.

Here is the background; the engines and the Racors were serviced in February. I am not sure if it was the time that passed or the fuel we picked up in Marathon prior to heading up to Bimini. There is no way to drain the bowls while under way.

I am having pepcocks installed on each bowl.

Has anyone done this? Can we drain any water off while the motors are running without cavitating the injectors?

My fear is that we get air in the Racor and the motors fail to prime.

We use additives when we leave the boat for longer than 4 weeks.

Thanks for any help.

Ken
 
A couple of thoughts...

First, this is the petcock for the bottom of the racors:

RAC-6451.jpg


And here it is in a cross section (part 15):

racordrain.jpg


You will not be able to drain water off while the motors are running as air will get sucked up through the valve. In fact, and this is important, you have to have that bolt/plug in the bottom of the valve. Turning the valve off alone will not seal them enough to prevent air from being sucked up into the racor. I found this out the hard way as after I installed them, I kept getting air in the lines. After priming after priming I finally stuck a flashlight up to the racor and saw air bubbles coming up from the petcock (I did not have the plug installed as I thought I didn't need it) and it looked like a bubbler in a fish tank. The suction is enough to pull in air but not allow fuel to leak out. Go figure...

It's also good to drain the crap out of these things on occasion as black asphalt like stuff will build up in the bottom of the bowls.

One other thought is you may want to keep an eye on.... I assume you have fuel coolers on the the engines that are part of the raw water circuit. If they develop a leak, they will start to put sea water in your fuel tank... they are on the return fuel circuit from the engine to the tank and keep the fuel tanks from heating up. Water will show up in your fuel tank/racors if they start to leak. Enough water in the fuel and you could have a catastrophic failure... so I would check the fuel coolers just to be safe. I actually replaced mine last year as preventative maintenance as I don't want them to fail when I'm not expecting it... It's like the riser thing on a gas boat.

Also, you WANT the water sensor at the bottom of the bowl as water sinks to the bottom (it's heavier than the fuel). If they were at the top, your engine would explode at the same time the water in the bowl alarm went off.

I thought you were going to install these things last year?
 
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One other thing... if you install these yourself, do NOT use the white teflon thread tape as it does not work with diesel fuel (it dissolves). You need to get the yellow thread tape/dope that works with diesel fuel... and don't get it anywhere near the top of the threads where it can end up inside the racor. You should carry some with you to seal up that bolt/plug on the bottom when you service them from time to time.
 
Gary, How do you keep so much information in your head? You Rock!! I printed your drawings out and will make sure there is a plug below the drain valve. So maybe I missed something, but if I add these, and drain the water off, how do they re-prime?

A while back I think Robski told me to run the pumps by turning the ignition on and off until they fill. I was told by a mechanic that would take quite a while to fill the 3 quarts.

Thanks again!

Ken
 
My racors are below the full fuel tank level so I just have to loosen the top and open the fuel valve on them and they prime.

You don't have to drain the racors to get the water out... I just remove maybe a 1/4 cup of fuel TOTAL from all four and check what is in the cup... no need to prime for that... and typically air does not go back up so I assume it's pulling fuel from the tank (I usually do this service with full tanks).

I do carry a 2 gallon jug of clean fuel and a 2 gallon empty jug for "dirty fuel"... The clean fuel is in case I need to prime. That happens when I am below 1/2 tank of fuel.
 
Gary, as usual thank you again. I believe the valve to the tanks are about the same level as the racors. Once the pepcocks are installed, I will drain a little and see if they prime themselves.

I used to carry a couple gallon tank of fresh diesel with me, but when I learned it took 3 quarts each to fill, I gave up. I agree it should only be a cup or so with the valves installed to drain the water and refill if gravity does not re fill the racors.

Thanks again.

Ken
 
Gary covered most of the points in your post, except.........You must be sure the Racors will prime. If they don't you can easily run the entire system out of fuel from the Racors to the injectors. Purging big diesel engines can be a real bitch. The safest way to ensure priming is to remove the Racor lid and top it off by hand, then you know.

Finally, do not use any form of Teflon tape on fuel fittings, for 2 reasons. The thread profile or cross section for fuel fittings is slightly different than for regular NPT fittings. Teflon tape will ball up and come off in little pieces when the mating threads are thightened. Instead, just take along a small tube of Teflon pipe dope which will work its way in to the thread voids and will not get balled up. Teflon tape fragments in a fuel system are a whole lot worse to clean out than water and sludge. Instead of just changing a filter, you will have to completely disassemble the Racor canister and clean every part and passage in it.
 
Four Suns said:
My racors are below the full fuel tank level so I just have to loosen the top and open the fuel valve on them and they prime.

You don't have to drain the racors to get the water out... I just remove maybe a 1/4 cup of fuel TOTAL from all four and check what is in the cup... no need to prime for that... and typically air does not go back up so I assume it's pulling fuel from the tank (I usually do this service with full tanks).

I do carry a 2 gallon jug of clean fuel and a 2 gallon empty jug for "dirty fuel"... The clean fuel is in case I need to prime. That happens when I am below 1/2 tank of fuel.
Click to expand...

Gary, are you OK ? Med's kicking in ? Age ? Mid life crisis ?
OK, don't get me wrong I like the low key Gary.... But where is the Gary of yesteryear ? The smart ass, the joker, the ???
It's OK, I turned 50 this year and just tonight the Mrs. and I got into it about my statement "I get older, but I refuse to grow up".....So I still like & respect but just wonder.....?
 
Ken,
Gary as always is head on. Rocking the ignition switch on and off will fill the racors. YEs it may take up 10 offs and ons but its so much easier .... And u dont have to carry a jug of fuel. The qsc will purge any air so no worrys about being air bound . Like Gary said u must cap the pet cocks.

Rob
 
Here's what they look like installed.....on my itty bitty 500MAs....

racorwithdrainandguage.jpg


I will +1 the idea to take them out and give them a 'REAL' cleaning. I just did all of mine two months ago. It's absolutely amazing what comes of the nooks and crannies....especially in the cyclone area where the check ball is....well worth the effort.
 
Since were talking about water in the fuel...
If there's enough water in the tank to reach the fuel pickup, why isn't that a major problem?

I read all the time about guys that get a bad batch of fuel, etc. and are constantly draining water out of their separators. But doesn't that mean there's a "layer" of water lying in the bottom of the tank to the height of the pickup? Wouldn't that cause additional problems with growth of various critters in the fuel?

Fortunately, I've never had so much as a single drop of water show up in the Racors in the three years I've owned the boat.
 
I had bad fuel ( 3 years ago ) which was WATER , some kinda spooge and SAND !!!! After the initial WTF's , some name calling and filter changes after 2 fuel drops Im hoping and thinking i got most of it out. ( I ran my tanks almost dry to get as much out as possible. ) My racors are pulled after the season looking pretty good. I have no science experiments in my racor bowls. But yea Im thinking i got a sandy beach in the bottom of my tank. Some good wave action while running will get the stuff to the filters. ( except the sand i think )

Rob
 
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