Raw water filter & fuel filter questions

[jeannieb]

Two questions:

I've got the Volvo D4-260 in my 25CC inboard. Volvo recommends the use of a sea water filter. The only raw water filtration CC installed for the engine is the simple, exterior strainer on the raw water thru-hull. Has anyone had any problems with this set-up? Or is the exterior strainer sufficient?

As for fuel filtration, I spoke to a tech-rep at Separ and asked him if he thought adding an additional in-line, primary fuel filter was a good idea considering the Volvo's common rail system. He said that doubling the filtration was unnecessary and ill-advised since it would only increase resistance in fuel flow. Some may disagree. Does anyone have any thoughts or experience with that arrangement?

Thanks

Steve

[CC28_NJ]

For the 1st question,
Never had a problem with external strainers on my 28, thought of changing them to internal stainers, but never really found the need to.

for the second question. The best Advice to give you is.

"go to boatdiesel.com
make contact with Tony Athens" (Backman), (I love this))

He is an expert on fuel filtratrion, of any make diesel.

Nick
01 28

[Tswann]

Filtration

If you have the Separ as a primary and Volvo's on-engine as secondary you do not need any additional fuel filtration. The Separ is a 10 micron and is a very effective/efficient filter and the on-engine is a 2 micron from Volvo. The fuel restriction is measured and checked by Volvo at Carolina Classic to certify the install -- any additional filtration will increase fuel restriction and be ill-advised and will effect warranty if a pump/fuel issue arrises.

I read a lot of Tony Athen's articles/post on Boat diesel and they are spot on. His article on fuel filtration, however, is aimed at mechanical engines (not common rail) and work on the assumption that 30 micron is primary and 10 micron is secondary . . . Applying this method to common rail diesels running with 10 micron and 2 micron filtration is not apples to apples . . . .

[backman]

Thanks

I've had no issues w/ the Separ 10/ Volvo 2 micron combination but I'm pertty anal about draining and flushing the Separs every 25 hr's and replacing them at ~75 hr intervals.

Any advice on how low sulfer fuel is going to affect us common rail diesel owners?

[jeannieb]

I've got 85 hours total time on my new CC25 and Volvo D4. Late last season I got a fuel system alarm. After looking down below, I figured it was just a clogged filter, but since it was rough and I was within a few miles of the beach, I just came in on idle power.

Although the fuel bowl appeared clean, after breaking it down I found no water but a good deal of sludge both on the centrifuge and in the filter. I had been using Bio-bore at maitenance levels routinely (as I always had with my prior Volvo KAMD-44).

I've read all of Tony Athen's stuff and spoken to the Separ rep as I mentioned earlier. I've also read Nigel Calder's latest edition of his book Marine Diesel Engines (highly recommended). Clader says that according to the authorities, "90% of diesel engine problems result from contaminated fuel." Well, my diesel engine experience doesn't support that statistic...but Calder does say that, following his precations, "In over 25-years of cruising [he's] never had an even moderately contaminated fuel filter."

Net result: I will not add an aditional Separ filter; I will try the Algae-X fuel additive rather than Bio-bore (but I'll use it sparingly and only as a profilactic measure as Calder recommends); I will begin this new season routinely back-flushing my primary every 25 hours and change out both primary AND secondary every 50 hours and, most important of all; I will filter my fuel as it is being added to the tank with a Baja filter and routinely sample the bottom of the tank for water, sediment and sludge.

Thanks for everyone's response...good advice all!

[code blue]

fuel and separs

Right on, I have my 28 05 for 16 months and twice have had serious issues. As you know these common rails are a different breed. Need really clean fuel and very sensitive on fuel flow to the injectors. When i shipped the boat to hawaii I had a major algae water problem from transport, also was sucking salt water to tank so fixed all that once after wasting many separs and polishing fuel. things were great till last month, only would change separs at the 100 hour mark and no issues. Introduce low sulfur fuel and decreased resistance to microbes(sulfur as you know has antibiotic properties hence this is why we use it effectively in medicine). Now your fuels resistance to microbes is less. So broke down last month, filters clogged...opened separs and gooey algae choked the filters. Had fuel polished again and sucked out 5 gallons of gooey floating algae and supertreated everything. I always refilter my fuel from distributor and was using biobohr but I will admit at a bit lower than reccomended, I thank my volvo rep here for that one as he said it is not needed every fill and especially if you use your boat weekly which I do. So I too am trying AJX additive and will let you all know, treated the tank with this "tank tonic" to kill everything(any experiences?). Now am still trying to get little particulates out. Ran the boat in rough seas for 10 hours to slosh the tank as the baffolds due restrict fuel movement and changed the filters once and suspect I will have another trip or 2 left to do this. My suggestion is if your alarms sound at high rpm slow down jut to forward and change one at a time as you can really get sick with your head upside down in 4-6 foot seas. You will do no harm as the restriction at the higher fuel rate will not be a big deal while you change filters unless at low RPM she runs erratically, then change em both and risk the sickness. I feel as though I am becoming a pro at this unfortunately and other than the fuel issue and a rear main seal leak and having to replace all the computers(at volvo's cost) these engines seem like they will run forever with proper maintenance. I keep three sets of separs in plastic bags on the boat now!
One question though, I was told you can reuse the filters and clean them...HOW...? And I do not see backflushing to be the anwer when that fine film sits on those folds backflushing will not be the answer..Aloha
Does anyone have the number for the separ filter guy I am somewhat desperate to get them ASAP as you can imagine!

[jeannieb]

I don't have their phone number handy, but I did get it off their website (if I remember it's separfilters.com or something similar). the tech-rep I spoke to was friendly and very helpful.

Steve

[dtaylor]

Steve,

I installed a raw-water filter on my boat the first year I had it because of all the grass we have at home. I installed a graco raw water filter and have been happy with it so far. I would be glad to show you the filter set-up and will have the boat around home this weekend if you would like to see the set-up.

[Armageddon]

The reason to have these filters is to prevent anything from getting into the engine(s), PERIOD. I have twin screws 260's and filters are huge to keep your engines well maintained and performing well.

SEA STRAINERS
If you are in a weedy environment, which almost every boater is faced with, you MUST invest in an external hull strainer, like the one Groco offers. Even though you have an internal strainer that you are supposed to check regularly, the external strainer prevents larger particles like seaweed from clogging your internal strainer inside the boat. You can have constant engine overheating issues if you dont invest in an external hull strainer. Try this link to see what you need: http://www.boatersworld.com/product/356221085msk.htm

PRIMARY AND SECONDARY FUEL FILTERS
Just like the sea strainer, you also need a primary and secondary fuel filter. I personally think a 10 micron filter is not a good option for a higher horsepower engine because it will restrict your fuel flow to the engine much faster. I have a 30 micron filter (Racor R90P) and this will keep your fuel flow high and still trap all of the "junk" that is put into your fuel tank from the fuel dock, etc. If particles get past this filter, your engine's fuel filter will trap everything else. By having both filters, you prevent future problems affecting your engine and it give me peace of mind when I'm travelling 80 miles offshore. I would rather replace the fuel filter outside of the HOT engine room in 3-5 foot seas instead of waiting for a problem to arise in the engine room.

Don't forget to replace your filters every 100 hours, or whatever your owners manual suggests.

Hope this helps ....

[Split Decision]

PRIMARY AND SECONDARY FUEL FILTERS
Just like the sea strainer, you also need a primary and secondary fuel filter. I personally think a 10 micron filter is not a good option for a higher horsepower engine because it will restrict your fuel flow to the engine much faster. I have a 30 micron filter (Racor R90P) and this will keep your fuel flow high and still trap all of the "junk" that is put into your fuel tank from the fuel dock, etc. If particles get past this filter, your engine's fuel filter will trap everything else.
....[/QUOTE]

30 micron filters are fine for the mechanical engines but the 10s are a requirement for the primary filter on the commonrail engines.

[Bullish]

I took a course at Mack Boring a couple of years ago. I recall him preaching not to use anything smaller than 30 micron because it is too fine a filter to start with.

[Armageddon]

EXACTLY, 30 micron and/or 10 micron, they both assist in filtering your fuel before it gets into your engines. The primary fuel filter is the first one in line coming out of the tank and should be at a higher micron level. Your secondary fuel filter on your engine should be 10 micron or less anyway. All you are doing is restricting fuel flow and starving your engines with ANOTHER 10 micron on your primary. When you're running offshore for 3-4 hours each way in moderate seas, all the junk that may be in the tank from your last gas dock fill up is going to clogg the 10 micron much faster than a 30 micron.

When it comes to the marine environment, you have to have BOTH, a primary (30 Micron recommended, to be replaced every 500 hours or every 2 years, whichever comes first) and secondary fuel filter(10 micron or less, EOM recommended from the manufacturer of your engine, replaced every 100 hours) in the fuel system of each engine on your boat.....