Do I need fuel polishing?

[sunchaser]

What you need to do is drive your boat.

Burn some fuel, have some spare filters onboard of course, but run the boat more.

+2. Underuse, likely the major cause of fuel related (and other) recreational boat issues IMHO.

 

[BandB]

I'm not sure this guy has an actual problem.

Nor am I. Maybe Racors just did their normal job.

 

[SeaBreeze]

"The other had the yuck clog at the tank outlet."

A common hassle, usually bug bodies and waste.

IF the pickup is removable it is sometimes possible to create a bag with lots of area out of metal and hose clamp it on the fuel pickup .

Recently the bride bought a fat splatter screen at IKEA , a couple of bucks , that has the finest SS mesh I have ever seen.

I'm dealing with a significant case of bioscum in my tanks (looks like pond scum). I did a similar thing to what FF said after I cleaned all of it out that was reachable. I have 4 full height chambers (baffles) in each tank so short of installing 4 access ports you cant get to every chamber. I cleaned the chambers I could reach and then took a gatorade bottle and drill a few dozen small holes in it starting 1 inch from the bottom of the bottle. After drilling a pickup tube sized hole in the top, I slipped the bottle over the pickup tube. The bottle keeps any bioscum out of the tube but lets fuel in. Over time, I expect that the bioscum will works its way to the chamber I can access. When it does I will remove it. This has worked really well so far.

 

[SeaBreeze]

i'm dealing with a significant case of bioscum in my tanks (looks like pond scum). I did a similar thing to what ff said after i cleaned all of it out that was reachable. I have 4 full height chambers (baffles) in each tank so short of installing 4 access ports you cant get to every chamber. I cleaned the chambers i could reach and then took a gatorade bottle and drill a few dozen small holes in it starting 1 inch from the bottom of the bottle. After drilling a pickup tube sized hole in the top, i slipped the bottle over the pickup tube. The bottle keeps any bioscum out of the tube but lets fuel in. Over time, i expect that the bioscum will works its way to the chamber i can access. When it does i will remove it. This has worked really well so far.

 

[Vadim]

Being new to diesel- quick question...
Will primarily cruise around home in the bay so wondering if I should fill-up (400 gal) and use during the year or fill less quantity and add fuel more often?

Thanks

You would be better to keep your tanks as full as possible at all the time. Less air in the tanks the better.

 

[Harlen]

Original poster has been scarce with details.

How much fuel burned since filter was new. How much calendar time. Did engine starve for fuel, or was it just a black filter on change? What size filter? 500, 900, 1000?

I'm not sure this guy has an actual problem.

160 gal burned in 6 months.

Engine did not starve for fuel as vacuum gauge just hit the beginning of the red.

Racor 900.

Filter usually lasts 300+ gal and was black colored (not asphaltene) when changed suggesting algae/bacteria growth. Had not seen this discoloration in the past.

Certified diesel mechanic said it does look like algae/bacteria in the tank.

So I believe I have a problem but the question is what to do about it, hit the tank with a shock of biocide and then run the engine changing filters as needed to see if it clears up (as many have suggested on this forum) or to do fuel polishing (suggested by the certified mechanic and, no, he does not do it.)

 

[SeaBreeze]

The fuel "polishing" is only as good as the access to your tank. Do you have an inspection port? Are there baffles in your tank? If there are baffles (especially top to bottom baffles) the polishing will be very limited. If you tank is open end to end and there is an inspection port that allows easy access to the interior then polishing can be very effective. If you do decide to polish, make sure the polisher has high return pressure on his system. If he does he can powerwash the inside of the tank which will allow the suction tube to get all or most of the contamination.

 

[Harlen]

I found data on my engine that says that 144 gph of fuel flows through the filters at 2400 rpm. This encourages me to try using the biocide and running the boat, as a lot of the fuel is getting filtered. If my Racor filters begin to last longer and get closer to normal, that would be a success. If not, I will need to spring for the polishing.

 

[OldDan1943]

I found data on my engine that says that 144 gph of fuel flows through the filters at 2400 rpm. This encourages me to try using the biocide and running the boat, as a lot of the fuel is getting filtered. If my Racor filters begin to last longer and get closer to normal, that would be a success. If not, I will need to spring for the polishing.

A fuel polisher can be used without running the main engine.
If your engine stops due to contaminated fuel, there is still the fuel polisher.
You can polish the fuel while you are changing the Racors, secondary filters and bleeding the system (if necessary).

I am not pushing a fuel polishing system. Suggesting it.

Question: if your boat has a day tank, how do you fill it?

 

[syjos]

You would be better to keep your tanks as full as possible at all the time. Less air in the tanks the better.

I don't think so. It has not been proven that partially filled diesel tanks will create water problems due to condensation.

There's been several threads discussing whether to top up tanks or not during the off season.

With large tanks, the fuel doesn't get used fast enough so gets old in the tank.

 

[dhays]

So I believe I have a problem but the question is what to do about it, hit the tank with a shock of biocide and then run the engine changing filters as needed to see if it clears up (as many have suggested on this forum) or to do fuel polishing (suggested by the certified mechanic and, no, he does not do it.)

OK, great information. If it was me, I'd probably just do a shock treatment with a biocide, install a dual filter (not hard to do but they are expensive), keep an eye on the vacuum gauge and just plan on replacing filters more frequently. If the issue gets worse, then spend the money to have your tanks inspected and cleaned. Any fuel in the tanks should be polished before returning to the tank.



Unfortunately, we all tend to be talking about different things when we talk about fuel polishing. Others will disagree but here is my take.


- Fuel polishing is more than just running fuel through a filter and water separator. BandB's post earlier described it well.


- Fuel polishing is NOT the same as tank cleaning. They are two separate things. Fuel polishing is restoring fuel to a high quality usable condition. However, what point is putting good fuel back into a tank that has problems. Therefore it makes sense to remove the fuel, polish it, clean the tank, and then return the polished fuel to the tank. But don't conflate the two things.

 

[Ski in NC]

Harlen- based on the latest info, I'd do a biocide treatment and continue running. Change the racor a bit more often as filter might clog from dead bugs. But it is doing its job just fine, just keep an eye on the vac gauge. Fuel polishing is not real successful unless tank has access to all parts of the tank (rare).

 

[syjos]

I would do the biocide shock treatment and run the engine.

But before you leave the dock:

Check for any water in the tank.

Have plenty of spare filters. Use an element with a lower micron rating than the engine mounted filters so the yuck doesn't go into those hard to change elements.

If you don't have one, install a vacuum gauge to monitor the element.

Practice changing the filter and bleeding if required.

A gallon can of diesel to top up the element if yours doesn't gravity feed.

 

[mvweebles]

I had 15+ year old diesel in my tanks before I departed San Francisco for Ensenada last year. The port tank smelled like linseed oil, not diesel. My mechanic who I've known for 25-years (Eric Mashbir - a genius) was seriously concerned. But disposing of diesel in Sam Francisco is seriosuly expensive ($4k - at least). We treated with 4x dose of Stanadyne and diluted as best possible with fresh diesel. I did about 20-hours of sea trials and the old Perkins 4.236 ran fine. I had a dual racor 500 installed and decided to go for it with a batch of spare filters. BTW - knowledgeable mechanics I have met do not recommend running 2-micron in the racors. Sounds counter intuitive but given how much these folks make, I'm inclined to honor their knowledge.

I departed SF and headed south 500nms to Ensenada in 75 hours and burned about 80-gallons (guesstimate). Vacuum came up about 5-lbs over the course of the trip, and that's it. Perkins ran perfectly throughout.

I attribute this to an old-school diesel engine. And low fuel flow.

When I got to Mexico, I had the rusted fuel tanks replaced with fiberglass. The old diesel was so dark and worn that it could not be given away. Even in Mexico to the fishing docks. Go figure.

My point in this long story is that one solution does not fit all. Newer common rail engines are a bit more finicky. Also, hours alone are not the story. In 100-hours (trip plus sea trial), I burned 100-gallons or so. Not a lot to run through racors. A larger engine or faster boat may have run 500-gallons in 100-hours.

 

[syjos]

BTW - knowledgeable mechanics I have met do not recommend running 2-micron in the racors. Sounds counter intuitive but given how much these folks make, I'm inclined to honor their knowledge.

.

The issue of 2 micron elements in Racors have been discussed to death in the last 25 years in Passagemaker magazine, Trawler Forum and many other places.

I'm not sure if the debate ever got settled but I have been using 2 micron elements for close to 35 years with no issues.

With the 2 micron elements in the Racors, I went 19 years without replacing the engine mounted filters on Sandpiper.

I can see why mechanics do not recommend the 2 micron. To change the engine mounted filters and bleed the system is maybe 1/2 hour plus the cost of the elements. That's lost income for the mechanic and/or the shop.

I'm not saying that the mechanics or diesel shops are being dishonest. Since the 2 micron debate has never been settled, not recommending the 2 micron may be their belief. And if they are on the fence about 2 micron, they'll be cautious and not recommend the 2 micron while protecting their bottom line.

 

[FlyWright]

I had 15+ year old diesel in my tanks before I departed San Francisco for Ensenada last year. The port tank smelled like linseed oil, not diesel. My mechanic who I've known for 25-years (Eric Mashbir - a genius) was seriously concerned. But disposing of diesel in Sam Francisco is seriosuly expensive ($4k - at least). We treated with 4x dose of Stanadyne and diluted as best possible with fresh diesel. I did about 20-hours of sea trials and the old Perkins 4.236 ran fine. I had a dual racor 500 installed and decided to go for it with a batch of spare filters. BTW - knowledgeable mechanics I have met do not recommend running 2-micron in the racors. Sounds counter intuitive but given how much these folks make, I'm inclined to honor their knowledge.

I departed SF and headed south 500nms to Ensenada in 75 hours and burned about 80-gallons (guesstimate). Vacuum came up about 5-lbs over the course of the trip, and that's it. Perkins ran perfectly throughout.

Gotta love the Perkins 4.236. It's a very durable and forgiving engine.

 

[mvweebles]

The issue of 2 micron elements in Racors have been discussed to death in the last 25 years in Passagemaker magazine, Trawler Forum and many other places.

I'm not sure if the debate ever got settled but I have been using 2 micron elements for close to 35 years with no issues.

With the 2 micron elements in the Racors, I went 19 years without replacing the engine mounted filters on Sandpiper.

I can see why mechanics do not recommend the 2 micron. To change the engine mounted filters and bleed the system is maybe 1/2 hour plus the cost of the elements. That's lost income for the mechanic and/or the shop.

I'm not saying that the mechanics or diesel shops are being dishonest. Since the 2 micron debate has never been settled, not recommending the 2 micron may be their belief. And if they are on the fence about 2 micron, they'll be cautious and not recommend the 2 micron while protecting their bottom line.

I have about 18,000 offshore miles under power (past delivery skipper running between Alaska and Mexico). I appreciate that every captain must make their own decisions. I have had no issues whatsoever following the engine manufacturers specs, and listening to mechanics and engine reps who have earned my respect over many years. I can honestly say their #1 priority is my safety and best wishes for a successful delivery. When they tell me to follow the recommendations and run 10-micron in racors, I listen.

 

[Ski in NC]

The issue of 2 micron elements in Racors have been discussed to death in the last 25 years in Passagemaker magazine, Trawler Forum and many other places.

I'm not sure if the debate ever got settled but I have been using 2 micron elements for close to 35 years with no issues.

With the 2 micron elements in the Racors, I went 19 years without replacing the engine mounted filters on Sandpiper.

I can see why mechanics do not recommend the 2 micron. To change the engine mounted filters and bleed the system is maybe 1/2 hour plus the cost of the elements. That's lost income for the mechanic and/or the shop.

I'm not saying that the mechanics or diesel shops are being dishonest. Since the 2 micron debate has never been settled, not recommending the 2 micron may be their belief. And if they are on the fence about 2 micron, they'll be cautious and not recommend the 2 micron while protecting their bottom line.

If you ran your boat 19yrs without replacing the secondaries, you lost a good bit of credibility. Filters degrade with age as well as dirt loading. No way would I run a boat with any filter that old.

 

[syjos]

If you ran your boat 19yrs without replacing the secondaries, you lost a good bit of credibility. Filters degrade with age as well as dirt loading. No way would I run a boat with any filter that old.

I changed the secondaries this summer after 19 years. I was planning a change at 20 years but had to replace the fuel pump, so changed early.

I cut the end off the removed filter and the element looked in good shape. It was clean except for the reddish black color. No deterioration of the element fibers.

With a 2 micron in the primary, how does dirt get into the secondaries? With a 2 micron primary, the secondary filters are just along for the ride.

I plan on going 20 years without replacing the current engine mounted fuel filters. Oops, I probably won't live that long or at least not boating by that time.

Credibility be dammed!

 

[smitty477]

I changed the secondaries this summer after 19 years. I was planning a change at 20 years but had to replace the fuel pump, so changed early.

I cut the end off the removed filter and the element looked in good shape. It was clean except for the reddish black color. No deterioration of the element fibers.

With a 2 micron in the primary, how does dirt get into the secondaries? With a 2 micron primary, the secondary filters are just along for the ride.

I plan on going 20 years without replacing the current engine mounted fuel filters. Oops, I probably won't live that long or at least not boating by that time.

Credibility be dammed!

"With a 2 micron in the primary, how does dirt get into the secondaries? With a 2 micron primary, the secondary filters are just along for the ride."
Perhaps read up on how staged filtration works and what beta ratings mean for filter passes.

"I plan on going 20 years without replacing the current engine mounted fuel filters."
No one is forced to follow engine manufacturers recommendations nor to follow filter manufacturer recommendations nor to follow well regarded techs that have worked in this area.
Every boat owner can do as they may at any time.

 

[dhays]

I felt I was living dangerously by letting my last on-engine fuel filter go two years.


Of course, I have a high pressure, common rail engine so it isn't as forgiving as others.

 

[mvweebles]

Good articles from Steve d'Antonio on the topic of 10-micron vs 2-micron in Racors (spoiler alert: he advocates following recommendations from engine/filter manufacturers because sequential filtration works better).

https://stevedmarineconsulting.com/primary-fuel-filters-2-10-30-microns/
https://stevedmarineconsulting.com/fuel-filters-simplified-2/?upm_export=print

 

[dhays]

Good articles from Steve d'Antonio on the topic of 10-micron vs 2-micron in Racors (spoiler alert: he advocates following recommendations from engine/filter manufacturers because sequential filtration works better).

https://stevedmarineconsulting.com/primary-fuel-filters-2-10-30-microns/
https://stevedmarineconsulting.com/fuel-filters-simplified-2/?upm_export=print

They were good articles, thanks for the links. I've been running 10 micron filters but the last change my new "ready" filter that I put in was a 2 micron filter. Steve's arguments are good ones so I may go back to the 10 micron. FWIW, my on-engine fuel filter is really pretty easy to change and the Cummins QSB 5.9 is self priming. So that filter change is pretty simple.

 

[smitty477]

Good articles from Steve d'Antonio on the topic of 10-micron vs 2-micron in Racors (spoiler alert: he advocates following recommendations from engine/filter manufacturers because sequential filtration works better).

https://stevedmarineconsulting.com/primary-fuel-filters-2-10-30-microns/
https://stevedmarineconsulting.com/fuel-filters-simplified-2/?upm_export=print

Agree with Steve's excellent best advice - along with Tony Athens and many others including dozens at boatdiesel.

 

[vtmackey]

2006 Mainship 34T bought new. 2000 hours on the engine and ValvTect diesel fuel used almost exclusively.

Racor filter showed black on surface and needed changing sooner than previously.

Mechanic says this is algae growth in the tank and that I need fuel polishing.

I boat in the Pacific Northwest.

Comments?

Get it polished, don't over think it, better safe than sorry. I couldn't and had to change fuel filters every 10 to 20 hrs while traveling.

 

[Paris]

Hi Harlen and TF Friends!

1. Harlen, you mentioned that your 34T has a Racor 900. Mine, also a 2006, has a Racor 500. I was wondering if when you bought it new it had the 900 or 500. Reason I am asking is because a mechanic indeed told me that the 500 might be a bit small for the single Yanmar 370hp and got me thinking.

2. Also, I am considering to change the existing single 500 with a dual/auxiliary Racor 500 filter, so as to always have a back up filter ready to go “at the turn of a valve”, should I ever get caught in a rough seas situation having to change the filter of a single Racor unit, which will be at least awkward or even dangerous if the engine stops. Also, I will relocate the existing single 500 to the generator (Kohler 8KW, 2006), which today has a Racor R12T and is rather small (not much filter area), if “attacked” by sludge/algae etc.

3. Actually, am considering the above change because that’s what happened to me recently: one morning, the generator engine wouldn’t start, due to its small Racor being clogged, which then clogged the engine fuel filter (also small is size) and eventually also clogged the fuel pump!!! Although the starter would manage to turn the engine, there was no fuel there, due to clogging. Imagine if that was the main single Yanmar engine in rough seas...! Now, the strange thing was that the Yanmar Racor 500 was only slightly blackened and obviously the engine would start and operate just fine. To add to the strangeness of the incident, the tank feeds the Yanmar from a very low point almost from the very bottom of the tank, while the generator is fed from a higher point of the tank, having less possibility to take in bad fuel or sludge etc!

4. Making the long story short, I feel that this contradictory situation happened because: a) there is some sludge/algae in my tank, but maybe not a huge amount, b) the generator has a small Racor filter prone to clogging and c) there is no vacuum gauge on the generator Racor for easy monitoring of what goes on inside the filter (there is one though on the Yanmar Racor 500). Therefore, the initial solution is to increase the size of the generator filter and to add a gauge, while on the Yanmar feed to change the single Racor with a dual auxiliary system, with a gauge. Now, if things get worse and clogging comes often, cleaning the tank the traditional way, by opening it to scrub and wash its bottom might be needed, which is a more complicated and expensive solution due to the ports that need to be made on the specific tank, which now doesn’t have any. Filtering or Polishing the fuel could help, but I understand that results will not be as drastic as the opening of the tank.

Sorry for the long post, but I felt I should share the incident and my thoughts with you all. Finally, thanks to all of you for sharing great ideas and making this forum a great place to be!

Best,

Paris
Mainship 34T, 2006, single Yanmar 370hp

 

[Harlen]

Hi Harlen and TF Friends!

1. Harlen, you mentioned that your 34T has a Racor 900. Mine, also a 2006, has a Racor 500. I was wondering if when you bought it new it had the 900 or 500. Reason I am asking is because a mechanic indeed told me that the 500 might be a bit small for the single Yanmar 370hp and got me thinking.


Best,

Paris
Mainship 34T, 2006, single Yanmar 370hp

Hi Paris,

I added the 900 when the boat was new after my mechanic also said it seemed a bit small. He showed me the spec sheet on the engine that said the "Maximum Fuel Feed Pump Discharge" is 3 gallons per minute at 3000 RPM which would be 180 gallons per hour. I usually run from 1800 to 2400 so I went with the 900 for more capacity.

And I see the wisdom of having twin filters to have a backup to switch to but will wait on that.

I also discovered, as you did, that my tank had no cleaning ports. I have decided to have the tank cleaned with one port added to see if this is sufficient. The tank has three sections with baffles between so the best procedure is to put a port to access each section.

All that said, I have 2000 hours on the engine and this is the first time I have had filters last a shorter time.

Harlen

 

[Paris]

Thanks for the feedback Harlen.

I will most probably go ahead with the twin 500 Racor. I need to find the appropriate location in the ER though. Cleaning of the tank may come at a later stage.

Take care.

Paris