Single or dual fuel filters?

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HeadedToTexas

HeadedToTexas

Guru
Joined
Jul 3, 2016
Messages
1,454
Location
Sandusky Bay
Vessel Name
Escape
Vessel Make
Mariner 37
My boat has a single Racor filtering fuel from two tanks to a single engine. Since it has just the "idiot light" indicator, I am adding the new second generation vacuum gauge and that process has me trying to decide if a single filter is enough protection for my single engine.

And if I am going to upgrade to a dual Racor system, should I consider upgrading to a Keenan system? Is that even an upgrade from Racor? Thanks folks.

https://www.keenanfilters.com/monohull-systems/
 
Don't look at a two Raycor system as primary and secondary. Look at it as a filter and a spare.

You don't hook the Raycors up to double filter the fuel. It is just a great feature to be able to throw a routing valve and have a fresh filter online

pete
 
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That's the way I understand it, though my post was less than clear. Definitely a filter and a spare. With a single filter, the spare is me hustling below to the engine room to swap out the filter in what Murphy says will be dire conditions. At that point, having a spare ready with a couple valve changes sounds very comforting.
 
Go dual, using one at a time. When one goes bad, turn the handle to use the second filter. Then replace the used one at your convenience.
 
Racor also offers a dual filter setup with a couple of valves for fast switch over.

Just without all the other stuff.

I have seen them , the Racor dual , in used stores and online so if not in a rush ahve a look..
 
What you seem to be thinking about is sequential filtering. Take a look at Seaboard Marine's offerings. Many here will disagree but my opinion that dual Racors are unnecessary and rarely useful. You will get responses talking about all those esoteric "what ifs", you are going sink to the bottom of the ocean. The picture is of Seaboard Marine dual filter head. The first filter is 20 microns, the second 10 microns. Monitor the gauge and change filters before a problem begins. 20210201_142145.jpeg
 
markpierce said:
Go dual, using one at a time. When one goes bad, turn the handle to use the second filter. Then replace the used one at your convenience.
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I have the dual Racors set up as Pete mentions. I think it’s a great feature to be able to reroute to the second filter and change the original filter at my convenience. I also have a sequential system as also mentioned. My first filter is 30 microns, the second is 10 and then my engine filter. Lots of peace of mind with this system for low cost.
 
Do you check the bowl with a flashlight every morning on pre-start checks? If so you can get along with a drag needle vacuum gauge on the T handle upgrade for about $90. You will know in advance of any clogging issues and can change the filter element in your single Racor before leaving. Racors' dual setup is pricey but more convenient.
 
This is very clear compared to single or dual engines.
 
Catalina Jack I agree that the need for the dual filter is not an everyday occurrence an if you typical cruise is only a few hours maybe you never need it. But I have used it twice in the Pacific between San Francisco and San Diego on two different boats.very rough conditions and at night so it was great to have the luxury of just changing the valve position. if you burn a lot of fuel or have a fuel polishing system that would also minimize the need. But In my opinion it is worth having for peace of mind.
catalinajack said:
What you seem to be thinking about is sequential filtering. Take a look at Seaboard Marine's offerings. Many here will disagree but my opinion that dual Racors are unnecessary and rarely useful. You will get responses talking about all those esoteric "what ifs", you are going sink to the bottom of the ocean. The picture is of Seaboard Marine dual filter head. The first filter is 20 microns, the second 10 microns. Monitor the gauge and change filters before a problem begins.View attachment 115356
Click to expand...
 
Dual Racors is the marine standard with diesel engines. If you don't happen to check them often enough the first sign you get will be your main engine sputtering. You will be happy you got the duals with the switch over valve. :banghead:
 
While I agree that many like having them for their own good reasons, I do not agree that they are a "marine standard". Far from it.
fgarriso said:
Dual Racors is the marine standard with diesel engines. If you don't happen to check them often enough the first sign you get will be your main engine sputtering. You will be happy you got the duals with the switch over valve. :banghead:
Click to expand...
 
Yes, peace of mind. Remember folks, the boater asking the question does not now have dual Racors. That would be a $1,400 addition for him. Also, use profiles play a part in this decision. One responder mentioned having to change while at sea. Yes, convenient but I can change one of those spin-on filters in less than five minutes. Close fuel valve, spin off, spin on, open valve, open bleeder, start engine. But, I have a walk-in engine room with everything accessible. That is part of the use profile. Every boat is different. Every boat is used differently.
Codger2 said:
:thumb::thumb::thumb:
Click to expand...
 
HeadedToTexas said:
My boat has a single Racor filtering fuel from two tanks to a single engine. Since it has just the "idiot light" indicator, I am adding the new second generation vacuum gauge and that process has me trying to decide if a single filter is enough protection for my single engine.

And if I am going to upgrade to a dual Racor system, should I consider upgrading to a Keenan system? Is that even an upgrade from Racor? Thanks folks.

https://www.keenanfilters.com/monohull-systems/
Click to expand...

Texas
With the exception of adding the vacuum gauge, why change anything more? Are you having problems with quickly clogging filters, dirty tanks or worse yet engine stumbles? Is your fuel supplier an iffy off brand with a rusty truck delivering fuel from shore? Are you cruising in areas with known bad fuel?

I suggest you go to the Sbarmarine website and read Tony's tips regarding fuel filtration. Beware the old adage "a perfect solution for a problem that doesn't exist." There are plenty of us cruising successfully with a single Racor per engine. Chasing the holy grail of marine fuel filtration is well and good, but whether Keenan, dual Racor or Tony Athen's setup look at it from a needs, piping, space and versatility basis.

Question, how often do you change your on engine filter?
 
"... hustling below to the engine room to swap out the filter in what Murphy says will be dire conditions"

I wouldn't make decisions based on cliches or as said before, solving a problem that doesn't exist. It's not difficult to keep clean, polished fuel in your tank(s), new O-rings on your flush fill ports and nasty little microbes from growing like a Petri dish. Also, if you do decide to buy a dual unit, there are off-name brands including high quality Chinese units. $1k buys you a lot of fuel for the season.
 
"With a single filter, the spare is me hustling below to the engine room to swap out the filter i"

Fuel rated hose is cheap , so why not locate the filters out of the Hell Hole where you can see , evaluate , and change them out if needed?

To my mind an "ideal" fuel system would be 2 tanks selected with a valve that also includes a return to that tank.

A dual filter bank monitored with a dash board DP (differential pressure) gauge that sees the suction before and after the filter , so you can observe if its the filter or fuel suction line that is the problem.

There would be an outboard bulb to prime the system and finally a refrigeration armored sight glass before the on engine filter to look for bubbles.

A Tank Tender would keep track of fuel volume.

This would be easy to live with and even better if the fuel tanks had a proper sump.
 
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Remember though, especially if you are installing or remodeling a filter system..

Every fitting, valve, elbow, etc. is a potential site to develop a vacuum leak.

pete
 
I initially had a dual Racor system on my Albin, installed by the previous owner. I thought it was great. However, on my maiden delivery voyage of 10 days I had many shutdowns. That was with 10 micron elements.
Got to my home port and changed the lift pump and flex hose, then installed a 30 micron Racor unit as a first filter, then fuel went to the 10 micron dual nit, then to the on engine filters.
In the next 14 years I never had one issue. I would change all the elements in the spring and never touch anything for a year.
Big fan of multi stage filtration.
Here's a pic of the system, and a pic of a "typical" 10 micron element after a year of service.
 

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sunchaser said:
Texas
With the exception of adding the vacuum gauge, why change anything more? Are you having problems with quickly clogging filters, dirty tanks or worse yet engine stumbles? Is your fuel supplier an iffy off brand with a rusty truck delivering fuel from shore? Are you cruising in areas with known bad fuel?
Click to expand...

I've never had a problem with my current fuel filter, and I have yet to change it. Hopefully I can always say that and change them annually as a preventative measure.

Adding the Racor gauge to replace the "dummy light" indicator seems smart to me and that opened the door to other upgrades in the fuel system. I'm just thinking and planning while I wait for boating season to open here on Lake Erie.

The engine room on the Mariner 37 is very accessible, but my fuel filter and tank valves are tucked in the least accessible corner. FF's observation that fuel line is cheap is a very good point. Facilitating maintenance is often better than spending to address the unlikely.
 
All filters recently replaced. All this talk about clogged filter at the wrong time. So next when I am looking for something to do I will install a bypass on the racor primary.
 
My boat operates from LA to Alaska. Meaning I only purchase clean fuel. I have been out there in some very snotty conditions. I check my Racor filters frequently as part of preventive maintenance. I have never needed to replace a dirty filter. I replace them every two years simply as a preventative measure. There is just no reason for me to upgrade from a single to a dual.

If I was traveling farther abroad I might have a different opinion.
 
I kept mine simple simple. One Racor 900 for the main, one 500 for the gennie. Blocking valves on each and a 1gal jug nearby. Both easy to get to in aft of ER. Both engines have their own spin-on secondaries.

Before I start a long trip I put a new element in each racor. Never had one clog even after covering thousands of miles. I change the secs like every other oil change.

On my engine if the racor gets a little cloggy, I can hear a tiny variation in rpm at planing speed. Tiny, but detectable. I know to throw in an element at next stop. Never had the engine struggle or quit from clogging.

I like the dual Racors, but just don't see the benefit outweighing the cost on my rig.
 
"Every fitting, valve, elbow, etc. is a potential site to develop a vacuum leak."

Perhaps,

"Facilitating maintenance is often better than spending to address the unlikely."

The practice of some offshore folks is to have a day tank that is high enough to gravity feed the engine and noisemaker..

Then the "hard to locate" vacuum leak becomes an easy to find ,a slow drip.

Worth the effort for no sea tow area adventures.





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I JUST installed dual Racors- you have the option of running them as a true Dual unit, or one at a time. After hassling some watery fuel on a delivery, I am SOLD on the dual.
 
Dual Racor 500's would suit your boat. eBay has them for $900 or a knock off for $360.
I have duals and you're right - engines will normally bog down in unkindly seas and throwing a lever is easier than trying to change a filter in those conditions. How do I know that?
 
READY said:
Catalina Jack I agree that the need for the dual filter is not an everyday occurrence an if you typical cruise is only a few hours maybe you never need it. But I have used it twice in the Pacific between San Francisco and San Diego on two different boats.very rough conditions and at night so it was great to have the luxury of just changing the valve position. if you burn a lot of fuel or have a fuel polishing system that would also minimize the need. But In my opinion it is worth having for peace of mind.
Click to expand...

Exactly. Very convenient at the most in-convenient times. :dance:

In addition, I feed from only one tank at a time, thus, if filter fills with whatever bad, I would switch tank source and spare racor at the same time.
 
For a single engine boat Triple, two running in parallel at all times, one for standby all same micron. That’s what we run on tow boats. We change filters every 500 hours. If in between the filters get gummed up you swap over to your single and put yourself in a safer position than you were in because they never clog up at a convenient time and change your twins at first available time and open one of the new ones. If it clogs up once you are prob going to be changing them fairly regularly shortly after that so it’s nice to have two in running in parallel to stretch out filter swaps. Although we go through prob an average of 20,000 gallons of fuel a month.
 
High Wire said:
Do you check the bowl with a flashlight every morning on pre-start checks? If so you can get along with a drag needle vacuum gauge on the T handle upgrade for about $90. You will know in advance of any clogging issues and can change the filter element in your single Racor before leaving. Racors' dual setup is pricey but more convenient.
Click to expand...

I put LEDs behind all my Racors so I can turn on the engine room lights and see what is/isn’t in the bowls without a flashlight. It is much easier to see with them backlit than using a flashlight. No reflections from the bowl. And no searching for the flashlight that didn’t get put back where it belongs...
 

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My boat came to me with dual Racors. I use one at a time and have only had to flip over to the alternate once. My on-engine fuel filter is totally clean at oil change time. I did put on the Racor vacuum gage that has an indicating needle. It’s the only way I can check the vacuum reading...

My fuel tanks are plumbed a little differently. There are two, 300 gallon tanks. The engine is set up to always draw from both via a crossover. The only time the crossovers are closed is when I’m taking on fuel. The fuel return is at a high rate and goes only to one tank, so running from one tank could quickly run a tank out or overfill it....
 
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