Black Racor Primary filter element

[Brian Brown]

I posted this same question on Boat diesel and received a few good comments. I thought I would try for a few more opinions. History: I purchased the boat a year ago 34 Mainship Pilot twin 4LHA-STP Yanmars. The previous owner had fuel tank issues when he purchased the boat in 2012 and had the tank (240 gallon aluminum tank) Cleaned ( Polished ) I have the report. He had the filters changed a couple of times a year and maintained the boat but only put 500 hours on the engines in the time he owned it. When I purchased the boat the engines had 850 hours. When I purchased the boat I could see some crud in the bowls or the Racor. I replaced both Primary and secondary filters and then ran the boat to a Boat yard where I would do some work on it and get it ready to do the LOOP. When I got to the yard, 185 mile run and 25 engine hours I noticed some more crus in the bottom of the bowls. I then replaced the filters and the boat was put into storage. While in storage I opened both sides of the tank 6″ access covers on the top of the tank and drained the tank from the fuel valves on the bottom of the tank. I removed 85 gallons of fuel and separated a small amount of crud and water when draining ( Method) I used a 5 gallon pail open top to inspect every gallon of fuel removed and got maybe a gallon of crud and water. The tank looked fairly clean. I wiped all areas that I could get access to with a rag and arc penetrating oil to help loosen any film on the sides of the tank and the bottom. There is a 2′ wide area of the tank that has a bulkhead on each side that I did not have access to. At the bottom of this area is where my fuel valves are right at the bottom. There are three valves one for each engine and one for the generator. My boat does not have a generator so I made this my tank drain valve to check the bottom of the tank for water or settled crud. I did remove each valve and this gave me enough access to run a swab on a stick to check the bottom section of the tank for crud. There was a little so I did it until clean swabs came out clean. I thought this tank should be clean enough to give me no grief. I added fuel in 5 gallon increments until I had 100 gallons of fuel in the tank while the boat was in heated storage. I added Pri-D fuel stabilizer.

I launched the boat in August of 2022 and the first thing I did was fill the tank 230 gallons with Pri-D additive. We left and I cruised everyday an average of 6 hours a day burning a little over 500 gallons of fuel and adding about 125 hours to the engine. I am running theses 4LHA’s at 1600 rpm with an occasional 2600 rpm run and always a check of WOT Starboard 3400 and Port 3300 rpm? Same props and props were checked by a reputable prop shop in Chicago Air Marine. At about 120 hours I noticed a drop in Rpm port engine only to 3150 rpm there was about a 1/4 inch of travel that the throttle stick did nothing. I felt this was fuel starvation. I removed the 500 series racor 10 micron element and would it was black in color. No slimy build up not rally plugged up with a lot of crud. Just black! I put a new filter element in and the engine 3300. The starboard engine was not effected. I did replace the filter any way Starboard side and it was black and looked the same as the port. ( they run off the same tank and the fuel valves are no more than 8″ apart.)

I added another 150 gallons of fuel and ran the engines for another 30 hours. I did my 200 hour service which included Primary fuel filters ( they only had 30 hours but I like to keep it all in sync) The filters again were black. Not slimy just black they didn’t seem like they were restricted. I cut one of the elements up an tried to see what the crud might be. It appears that there is very small black particles that were floating around and some laying on the top of the turbine element. Not much but visible.

My question after this long description is what is this and is it normal to have black filters coming from what should be a clean tank? I have pulled samples off the Botton of the tank and the fuel is clean with no evidence of water or any debris.

I assume I am returning a lot of fuel back to the tank with me running at 1600 rpm. Is this heating the fuel too much? The fuel tank like most boats is in the engine room so the fuel does get warm. Is this just residual grud that is built up in a tank in areas that I can’t see? Did I get some bad fuel somewhere? Is it normal to have filters look black after running fuel through them? I am changing the filters in the next few days to prepare for a 170 mile open water trip in the Gulf of Mexico. I will post pictures of the filters removed then.

Brian

Topic

[pwrobert]

The other comment addressed

You said you don’t like electrical fuel gauges – and I agree that typical senders with swing arm setups are crap.  But consider three other options.  My boat uses all three.

Regular electrical gauges attached to Centroid senders.  These have no moving parts and are ordered to fit your tank depth so come pre calibrated.  They can work with Analog needle or digital gauges.

NMEA digital tank senders which also have no moving parts.  Maretron makes one TLM100 and after calibrating they send fuel levels to your NMEA 2000 system for review on your chartplotter or whatever.

Lastly – for a totally non electric fuel gauge look into a Hart Systems fuel gauge.  It reads out fuel level in inches left in the tank and works by using the little air pump to purge out the measuring tube installed into the tank and reading the inches of fuel that comes back up into the 1/8″ tubing.  Only shortcoming to this unit is that it can only be read from one location.  In my particular case the Salon.  While most of my piloting is done from the Flybridge.

 

1 user thanked author for this post.

Brian Brown

[Brian Brown]

Thanks for all the replies. I believe the gauges are in order. I agree with Tony and Clark the 500’s are probably not the best choice and the 900’s would be a better choice with more filtering capacity. That said the boat is 20 years old and has had theses in it without issue. The original owner did have some fuel issues about 12 years ago and the next owner that I purchased the boat from had the tanks polished and showed me service records of all the fuel filter changes he had done and kept the fuel conditioned. He was not a DIY boat owner he had all of the work done by a marine service center. I still did not trust the tank. That is why I opened it up and from what I could see it was clean. I know there is no water in the tank and any fuel sample I take it looks clean clean. My plan may be to install larger filters with gauges. In the meantime I may use the 500’s with gauges. I am cruising now, Made a trip from the Panhandle Florida to the peninsula of Florida yesterday. (Gulf of Mexico) 10 hour run without issue. Checked WOT rpm starboard 3400 and port 3250. Still feel there may be some fuel starvation on port side even with clean filters. The Gauges will be the first troubleshoot tool for that I think.

My question still remains is it common for a 20 year old fuel tank to have the residual Ashphaltene ( black particles) ?

[donald roth]

Visible buildup on filters doesn’t necessarily mean they’re ready for replacement, it does mean that they’re doing their job.  A vacuum gauge between the filters and the pump is the only sure way to accurately assess the condition of the filters.  <br />If you read deep into the filtration articles, you’ll find that filtration actually improves as the filter “cakes”, but there again, only a vacuum gauge can tell you when it’s actually due for a change.  <br />I’ll second Robs recommendation of the DD filters, I went through the mill with fuel problems before I discovered them, not a glitch since, even with one incident where I took on several gallons of water in fuel.  The DD filters saved the injector pump, and I was successful in draining off the rest of it.

 

 

 

[Rob Schepis]

My current boat originally had Racor 900’s with 10 mic filters which I switched out to the SMX DD setup.  Look at these two photos when I cut open my last chance (on-engine) filters. One photo is 150 hours with the Racor ahead of it and the other photo is 160 hours with the SMX DD installed.  Very noticeable improvement.  (Look at the color of the pleats, Don’t mind the visible particles near the end of the filter, that’s from sawing open the metal casing)

1 user thanked author for this post.

Tony Athens

[Tony Athens]

This is my take……………………. Let’s see the inside of the last chance on-engine filter  If that filter is black ( doubt it), then your current filter system is sending crap to the engine ..  If that filter is “tan-ish”, then I’d add a spin-on  20-30 Mic primary Mud & Crud filter before your   Racor 500 as that will give you 5X ++ the  time between dealing with your Racor and add another layer  of protection to the system 

On another note————IMO, a  RACOR 500 is too small capacity wise  for any diesel propulsion engine above 100 HP or so, especially with a Injection pump like your have…

[Clark Leighs]

I think what you are seeing is ashphaltene.    It is residue of old diesel.    As long as the tank is clean of microbe activity and the filter indicates that from the no slime comment then the Ashphaltene is the most likely.     

Have you sent a sample to a good lab?   Both Caterpillar SOS and Blackstone among others can do this work.  THey may be able to tell you with less guessing what the problem is,  microbes or ashphaltene. Take some from the tank and from the filter.

It, ashphaltene should go down as you clock hours however it may be slow to do so.    It will have plated out onto the tank surfaces and can be tenacious.

FOr what you are doing the initial filter may be too small.  NOt the micron rating but the dirt holding capacity before causing trouble.  

THere are a couple of  things I will suggest to at least consider.    Get and install a vacuum guage with the telltale needle such as Seaboard offers just after the secondary filter.     You could put two in the line, one immediately after the  primary filter and then one after the secondary filter.    This way you will have a warning of the building flow loss before it causes trouble. 

Get a larger filter or twin the one you have.   The larger unit will give longer clog up time.    The twinning will also do that although you could valve them so a flip of a valve or two will bring the clean one online and close the other down.   

It would still be a good idea to install the vacuum guages though as a warning. In the case of twin filters and valves both filters must be primed before they are needed.   Always turn on the one to come into use first , then shut the one to be isolated off.

If you go with a larger unit then keep your current one as a spare to be used when needed. I tried looking up your other post on B.D. but no go.     You must have used a different name.  

  As you are going be sure you have lots of spares on board. 

Just my thoughts. 

I found your other post and Began has a point also.

 

 

[Brian Brown]

I am posting photos of the filter. I drained both filter housings and there was no evidence of water or crud in the bowls. The fuel that drained out of the filters looked clean except for some fine black particles. The photo of the bowl does show some aluminum filings. Theses are the result of some filings that escaped when I cut the holes in the top of the tank when I cleaned it. I have (2) 6″ access holes on the top of the tank now to access the inside of the tank. I made 8″ aluminum covers that are fastened with (8 )10/32 machine screws. There is also a 1 inch tank aluminum tank bung welded to the covered so I can stick check the fuel level. I don’t like electric fuel gauges and don’t have flow meters.

The fuel tank has had 630 gallons of fuel run through it since I cleaned it. I have now replaced the fuel filters three times. The filters visually have not looked bad just black??? Again my question is why are they black? What is the possible cause.

Thanks in advance for any thoughts or answer.

Brian

[Brian Brown]

I hope to change filters today. I will take photos of filter elements, bowl, and fuel. Than you for the response.

[Tony Athens]

GOOD Pictures of what you “see” would  help

[Author]

Replies