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Racor fuel filter caution, advice

Frank Langer

1984 Ericson 30+, Nanaimo, BC
Hi,
The 120R diesel fuel filter began to sweat/leak at the top brass nut that snugs up the filter below. I contacted Racor/Parker, who advised that the newer model since 2018 no longer has that nut on top, and they don't have any parts for the older one any more. They suggested I buy a whole new filter housing $$$.
I considered this poor advice, thought I didn't have anything to lose by taking it apart to see.
Taken apart in 20 minutes, found 2 o-rings on that top piece. Took it to a local shop who replaced both for $5.00.
i reinstalled the whole thing, bled the engine, and was done in two hours, including my driving time.
So this may help someone if that same nut begins to leak, and is a caution for others to not necessarily follow the advice of manufacturers or experts without trying a simpler, cheaper fix first.
Frank
 

supersailor

Contributing Partner
If your old Racor is more than seven years old, replace it. I've had two failures due to aluminum cracking and I'm surprised how many others have had failures. The system is too critical to Mickey Mouse it.
 

Frank Langer

1984 Ericson 30+, Nanaimo, BC
If your old Racor is more than seven years old, replace it. I've had two failures due to aluminum cracking and I'm surprised how many others have had failures. The system is too critical to Mickey Mouse it.
Hi Bob,
I appreciate your concern and advice, but I'm curious if you know why so many of these filters are cracking. It's a pretty simple device, not really under any pressure, lubricated by the diesel fuel and not in an especially corrosive spot. Any idea what is causing the problem? I've had mine for 12 years, with only this O-ring problem so far.
Frank
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
I replaced our '88 Racor installed by the EY factory due partly-to-near-untraceable air leaks, and due to it being long out of production. In 2018 I replaced that newer similar-design Racor with a Racor 500. These systems do get old, and aluminum castings can develop a tiny crack due to some invisible casting flaw. Sometimes. There is constant vibration from the engine to be a possible cause, IMHO.
I decided that when I had to search for replacement filters, packaged with old O rings of unknown age (or sourced from the 'net, as NOS parts) it was better to bring the system up to current standards. I agree with Bob's take on this being a critical system. I have had to once trouble shoot a "vacuum leak" while away from home, out cruising, and only 'enjoyed' the experience because I was successful and did learn something. :)
And no, we never did find a measurable puddle of 'vacuum'.... !
:rolleyes:
 

Tin Kicker

Sustaining Member
Moderator
Hmmm -

The problem is not going to be with the aluminum unless somebody has cracked the threads at a fitting, there is mechanical damage, or something similar.

I've investigated a LOT of fuel system failures in aviation and yes, "partly-to-near-untraceable air leaks" have always been a problem in vacuum style systems as opposed to pressurized ones. It's long been known that this is simply because air molecules are so darned small, and entrained molecules will collect in whatever high point(s) where they can to create a bubble in the fuel lines. If this is downstream of the HP pump in a diesel, the bubble will also become a spring and prevent pressure pulses from opening the injectors. It's one reason that when rebuilding my fuel system I put a second pump upstream of the Racor to act as a prime pump and pressurize the system. (* See notes below) Fuel molecules are far bigger making them more difficult to pass through a microscopic opening.

The problem is going to be with almost anything NOT aluminum, and as Frank found, the o-rings are typically a second place to look. The surface of the older o-rings get a bit hard and can oxidize, while even new silicone o-rings can break down with the contaminates associated with being around an engine. I wrote "second place" because my first place to check would be any hose clamp.

Beyond that, I've personally done testing at a fuel hose manufacturer where we had hoses pass pressure tests with flying colors (data actually) and then entrain air when we ran them in a vacuum. The air was entrained right through the layers of hose material. These boats run vacuum fuel systems and I'm going to guess that the majority have at least one piece of hose more than 10 years old, so if clamps and o-rings don't cure a problem my recommendation would be to start replacing hoses. If that doesn't "get it" start looking at the fittings to see if some ancient pipe sealant has hardened.

* Notes:
*1. The pressure pump in my system still draws a vacuum between it and the tank, but the system then only has two connections and a single piece of approved fuel line.
*2. Running a pressure pump can defeat the water separation ability of a Racor.
*3. Marine fuel systems are generally vacuum rather than pressure, because when there is a leak the engine stops, you don't have a fuel spray.
*4. I put the pump in the pressure orientation to be able to prime the system and use it for a back-up, NOT for normal operation.

btw - The plastic Racor fuel bowls are a problem and subject of their own in an area where there can be a fuel fire. I went to an aluminum bowl with a water drain system that in series has both a valve and plug.
 

Frank Langer

1984 Ericson 30+, Nanaimo, BC
Hmmm -

The problem is not going to be with the aluminum unless somebody has cracked the threads at a fitting, there is mechanical damage, or something similar.

I've investigated a LOT of fuel system failures in aviation and yes, "partly-to-near-untraceable air leaks" have always been a problem in vacuum style systems as opposed to pressurized ones. It's long been known that this is simply because air molecules are so darned small, and entrained molecules will collect in whatever high point(s) where they can to create a bubble in the fuel lines. If this is downstream of the HP pump in a diesel, the bubble will also become a spring and prevent pressure pulses from opening the injectors. It's one reason that when rebuilding my fuel system I put a second pump upstream of the Racor to act as a prime pump and pressurize the system. (* See notes below) Fuel molecules are far bigger making them more difficult to pass through a microscopic opening.

The problem is going to be with almost anything NOT aluminum, and as Frank found, the o-rings are typically a second place to look. The surface of the older o-rings get a bit hard and can oxidize, while even new silicone o-rings can break down with the contaminates associated with being around an engine. I wrote "second place" because my first place to check would be any hose clamp.

Beyond that, I've personally done testing at a fuel hose manufacturer where we had hoses pass pressure tests with flying colors (data actually) and then entrain air when we ran them in a vacuum. The air was entrained right through the layers of hose material. These boats run vacuum fuel systems and I'm going to guess that the majority have at least one piece of hose more than 10 years old, so if clamps and o-rings don't cure a problem my recommendation would be to start replacing hoses. If that doesn't "get it" start looking at the fittings to see if some ancient pipe sealant has hardened.

* Notes:
*1. The pressure pump in my system still draws a vacuum between it and the tank, but the system then only has two connections and a single piece of approved fuel line.
*2. Running a pressure pump can defeat the water separation ability of a Racor.
*3. Marine fuel systems are generally vacuum rather than pressure, because when there is a leak the engine stops, you don't have a fuel spray.
*4. I put the pump in the pressure orientation to be able to prime the system and use it for a back-up, NOT for normal operation.

btw - The plastic Racor fuel bowls are a problem and subject of their own in an area where there can be a fuel fire. I went to an aluminum bowl with a water drain system that in series has both a valve and plug.
Thanks for the interesting and helpful replies!
Frank
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
Interesting info about air entering thru the hose wall. One more reason to replace ancient fuel lines, IMHO.
Thanks for the technical education.
:geek:
Another way-cool thread....
 

Christian Williams

E381 - Los Angeles
Senior Moderator
Blogs Author
I believe that hairline cracks in the aluminum casting of the Racor 200 series are common after 30 years or so. The filter is hung from the casting in a vibration environment. The crack admits air, and leaves no evidence, which makes it very hard to recognize.

On my first Hawaii sail the engine wouldn't run two days before departure and I found myself out of troubleshooting luck with Fourth of July weekend approaching and all boatyards booked for a month. I described the situation to the guru at The Boatyard, who said immediately: "it's not the filter, it's the housing. They crack."

Sure enough, under a magnifying glass, I found a hairline crack in the casting. Local West Marine had one new 200 in stock, I put it on the night before departure. I would never have found the crack without guidance.

IMG_0258.JPG
 

Pat C.

Member III
Hmmm -

The problem is not going to be with the aluminum unless somebody has cracked the threads at a fitting, there is mechanical damage, or something similar.

I've investigated a LOT of fuel system failures in aviation and yes, "partly-to-near-untraceable air leaks" have always been a problem in vacuum style systems as opposed to pressurized ones. It's long been known that this is simply because air molecules are so darned small, and entrained molecules will collect in whatever high point(s) where they can to create a bubble in the fuel lines. If this is downstream of the HP pump in a diesel, the bubble will also become a spring and prevent pressure pulses from opening the injectors. It's one reason that when rebuilding my fuel system I put a second pump upstream of the Racor to act as a prime pump and pressurize the system. (* See notes below) Fuel molecules are far bigger making them more difficult to pass through a microscopic opening.

The problem is going to be with almost anything NOT aluminum, and as Frank found, the o-rings are typically a second place to look. The surface of the older o-rings get a bit hard and can oxidize, while even new silicone o-rings can break down with the contaminates associated with being around an engine. I wrote "second place" because my first place to check would be any hose clamp.

Beyond that, I've personally done testing at a fuel hose manufacturer where we had hoses pass pressure tests with flying colors (data actually) and then entrain air when we ran them in a vacuum. The air was entrained right through the layers of hose material. These boats run vacuum fuel systems and I'm going to guess that the majority have at least one piece of hose more than 10 years old, so if clamps and o-rings don't cure a problem my recommendation would be to start replacing hoses. If that doesn't "get it" start looking at the fittings to see if some ancient pipe sealant has hardened.

* Notes:
*1. The pressure pump in my system still draws a vacuum between it and the tank, but the system then only has two connections and a single piece of approved fuel line.
*2. Running a pressure pump can defeat the water separation ability of a Racor.
*3. Marine fuel systems are generally vacuum rather than pressure, because when there is a leak the engine stops, you don't have a fuel spray.
*4. I put the pump in the pressure orientation to be able to prime the system and use it for a back-up, NOT for normal operation.

btw - The plastic Racor fuel bowls are a problem and subject of their own in an area where there can be a fuel fire. I went to an aluminum bowl with a water drain system that in series has both a valve and plug.
Good stuff. I can definitely say I've learned something today. Thanks for the post!
 

Tin Kicker

Sustaining Member
Moderator
I believe that hairline cracks in the aluminum casting of the Racor 200 series are common after 30 years or so. The filter is hung from the casting in a vibration environment. The crack admits air, and leaves no evidence, which makes it very hard to recognize.

On my first Hawaii sail the engine wouldn't run two days before departure and I found myself out of troubleshooting luck with Fourth of July weekend approaching and all boatyards booked for a month. I described the situation to the guru at The Boatyard, who said immediately: "it's not the filter, it's the housing. They crack."

Sure enough, under a magnifying glass, I found a hairline crack in the casting. Local West Marine had one new 200 in stock, I put it on the night before departure. I would never have found the crack without guidance.

View attachment 34590

Just for clarity, I'm not arguing that cracks can not happen in aluminum. What triggered my "Hmmm" was Loren mentioning an invisible casting flaw and those generally show up in a very short time after manufacture.

What Loren also mentioned and Christian repeated is about a fatigue crack, which is an actual failure. These develop over a long period of time when the metal is flexed or vibrated. If you suspect one, you can usually "fix" the problem temporarily to find it by spreading an adhesive or even grease over it. If it turns out there is a fatigue failure, be aware that it will only progress and become worse. You can usually strip the paint and use dye penetrant to find it if not visible under close inspection. On parts like these repair is usually not cost effective so replace it before the crack grows.

btw - The grease trick is for troubleshooting and emergency repair. It works as a fast way to find & stop vacuum leaks or to get to shore and should be cleaned before going back out.

Sorry if I'd caused some confusion.

Bob
 

Alan Gomes

Sustaining Partner
I replaced our '88 Racor installed by the EY factory due partly-to-near-untraceable air leaks, and due to it being long out of production. In 2018 I replaced that newer similar-design Racor with a Racor 500. These systems do get old, and aluminum castings can develop a tiny crack due to some invisible casting flaw. Sometimes. There is constant vibration from the engine to be a possible cause, IMHO.
I decided that when I had to search for replacement filters, packaged with old O rings of unknown age (or sourced from the 'net, as NOS parts) it was better to bring the system up to current standards. I agree with Bob's take on this being a critical system. I have had to once trouble shoot a "vacuum leak" while away from home, out cruising, and only 'enjoyed' the experience because I was successful and did learn something. :)
And no, we never did find a measurable puddle of 'vacuum'.... !
:rolleyes:
Add to this the fact that the Racor 500 is superior in every way: cheaper filters, MUCH easier to change (especially if you have to do it underway), massive filtering capacity, robust construction, etc.

Spend the money/cry once and be done with it....
 

TAPH2O

Member II
Someone with an Ericson 36c with a bukh20 please post photos of their raycor or similar fuel filter setup with pre electric fuel pump.
 

supersailor

Contributing Partner
Vibration in the engine compartment would be my best guess for failure. These old Universals love to shake and vibrate. The crack in mine could be seen when the filter was disassembled. The evidence was not apparent from the outside. My bet is that that filter was twenty years old. After looking at all the other filters on the market, the Racor was far superior. I may be overly cautious but I don't want an engine failure in the middle of the Dent Rapids or, for that matter while entering my berth. Its the same reason that you replace the bellows on your shaft seal every 7 to 8 years. It may last 20 years but it's not worth the increasing chance that it may fail as time goes on.
 

jtsai

Member III
Question about adding inline check valve between tank and Racor filter. According to this article from Parker/Racor, the Racor 500 has internal check valve ball preventing fuel flow back to tank.


Does this check valve ball really work when Racor is installed higher than the tank? Has anyone installed an inline check valve between tank and filter to prevent back flow?
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
Does this check valve ball really work when Racor is installed higher than the tank? Has anyone installed an inline check valve between tank and filter to prevent back flow?
The filter is higher than the (under a settee) fuel tank in our boat. There is no factory check valve in the supply hose from the tank. The OEM smaller Racor worked OK, and the new 500 does too. (just another data point...)

BTW, that linked article is excellent! I did not know the part about how far below the rim the "pick up" point is at.
 
Last edited:

jtsai

Member III
So if the fuel level in the Racor filter become very low and loses its prime after prolong no use, then the Racor check valve must not be doing its job and allowed fuel back flow to the tank. Are there other possible causes?
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
So if the fuel level in the Racor filter become very low and loses its prime after prolong no use, then the Racor check valve must not be doing its job and allowed fuel back flow to the tank. Are there other possible causes?
After sitting for 11 months during our complete re-fit and painting, our Racor 500 showed no air in the bowl and our engine started and ran with no problems. Since relaunch it has run for several long days with no hiccups.
I am puzzled as to how fuel might migrate out of it. (?)
 

jtsai

Member III
The mystery with fuel migrates out the Racor 500 seems to have been solved with cleaning and replacing filter seals. I found rebuild kit in stock at the local powerboat marina parts store, they stock a lot more fuel related parts for obvious reason. The kit also contains more parts than needed, did not know Racor 500 can have heater element.

The cone shaped seal supports the SS ball which functions as the internal check valve has to be placed the correct way: the ball sits on flat side of the seal, not the cone side. The old seal was rather stiff.

Diesel sludge settled in the bowl, turbine centrifuge and conical baffle are easily removed, otherwise the unit is squeaky clean, the filter does its job.

Removing the unit from boat takes more time than the actual rebuild and cleaning. Worthwhile project if you are running out of boat projects.
 

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windblown

Member III
The mystery with fuel migrates out the Racor 500 seems to have been solved with cleaning and replacing filter seals. I found rebuild kit in stock at the local powerboat marina parts store, they stock a lot more fuel related parts for obvious reason. The kit also contains more parts than needed, did not know Racor 500 can have heater element.

The cone shaped seal supports the SS ball which functions as the internal check valve has to be placed the correct way: the ball sits on flat side of the seal, not the cone side. The old seal was rather stiff.

Diesel sludge settled in the bowl, turbine centrifuge and conical baffle are easily removed, otherwise the unit is squeaky clean, the filter does its job.

Removing the unit from boat takes more time than the actual rebuild and cleaning. Worthwhile project if you are running out of boat projects.
"Worthwhile project if you are running out of boat projects." LOL
 
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