Fuel polishing system

[Goldenstar38]

I have been doing some fuel tank cleaning and was considering adding/making a fuel polishing system.
In doing so, I would like to use the lowest tank fitting where the valve is normally used for the fuel level sight tube. This will be the intake side to the fuel pump and filter. Then, the return side after the filter will be returned through the uppermost fitting where the top of the sight tube was. With 2 added valves, I can retain the sight tube.
Any problems in doing this?

 

[what_barnacles]

not if you tighten it up so she doesnt leak.

 

[kulas44]

Pull from the "low" side and return as far away as possible, aka "high side". Otherwise you just recirculate the same fuel.

 

[No Mast]

I think Kulas may be right, you may end up mostly polishing the same 10 gallons over and over.

 

[Goldenstar38]

Never thought of that. The tank is about 30 inches tall, 7.5 feed wide and about 2 feet deep. The fittings are to starboard side of tank. What if I could replace the top fitting and angle inside 90 degrees to port? (if at all possible) to direct return further from inlet? Or, maybe I'm just spinning my props, er, wheels!

 

[markpierce]

My builder and my yardmaster say a fuel polishing system is a waste of money. Only use mine now for engine priming and shifting fuel among several tanks for balance; these are very useful functions.

Fuel polishing/shifting pump:

 

[Crusty Chief]

Goldenstar, your on the right track. Ours is set up that way. Because we are away from the boat for a month or so at a time, I set the timer for Six hours for each tank (2) we also use it to ballast as Mark said.
If your using the boat a lot, you may not need to run the polisher, but it is nice to have.

Good luck!

 

[Bay Pelican]

Seems to be no disagreement that the lowest outlet is workable as the intake for the fuel polishing pump. This is what I use. My return to the tank is by means of the same inlet on the tank in which fuel is returned from the engine.

I use a very simple system, Walbro 40 gallon per hour pump, Gulf Coast Filter Canister with a Bounty paper towel as filter. System draws from the lowest outlet and returns to the highest inlet.

 

[Capt Richard A.]

I have been doing some fuel tank cleaning and was considering adding/making a fuel polishing system.
In doing so, I would like to use the lowest tank fitting where the valve is normally used for the fuel level sight tube. This will be the intake side to the fuel pump and filter. Then, the return side after the filter will be returned through the uppermost fitting where the top of the sight tube was. With 2 added valves, I can retain the sight tube.
Any problems in doing this?

I built a system for my 44' marine trader, I usually waited until I had less that half in each 300 gallon tank. I ran from one tank through the filters to the other tank, then all of it back through the filters to the first tank then half back to the second tank I do realize I repeated the process and it took a little longer but , I'm on boat time. I used the line from tank to tank when needed. I do know that the bloom time for algae/fuel break down is 10 days, so I kept that in mind. I did this at a dock or at anchor. Never ever had a fuel problem.
Also, just a note: I added a squeeze bulb in the fuel line before my intake to my engine. My wife or I could bleed the engine, in less than 2 minutes while under way. The little lever at the pump was a nightmare.

 

[dimer2]

You may find some of these threads useful.


http://www.trawlerforum.com/forums/s32/fuel-polishing-24369.html


http://www.trawlerforum.com/forums/s32/fuel-polishing-question-16614.html


http://www.trawlerforum.com/forums/s6/fuel-polishing-system-filtration-questions-10689.html


http://www.trawlerforum.com/forums/s6/fuel-polishing-7347.html


http://www.trawlerforum.com/forums/s6/fuel-polishing-6314.html

 

[O C Diver]

Seems to be no disagreement that the lowest outlet is workable as the intake for the fuel polishing pump. This is what I use. My return to the tank is by means of the same inlet on the tank in which fuel is returned from the engine.

Have a similar setup on my 2 tanks. Fuel is drawn from the lowest point in the forward part of the tanks and returned with the engine fuel return at the furthest point in the rear.

I usually waited until I had less that half in each 300 gallon tank. I ran from one tank through the filters to the other tank, then all of it back through the filters to the first tank then half back to the second tank I do realize I repeated the process and it took a little longer but , I'm on boat time.

Did this at the end of my 18 month refit process. Pump all the fuel into one tank, then back to the other, then repeat the process. There was still some residual crud that has come out in the filter, but the majority was picked up in the back and forth fuel polishing.

Ted

 

[kulas44]

I have used the small 12 volt pumps, Walbro mostly, for fuel polishing but find they are way to slow. I still like them for priming and filling filters. A 12 volt transfer pump, like the ones used in ag applications for filling machinery from a truck mounted tank, is much better and will move fuel fast enough to actually stir it up a bit. Personally I like a 120 volt gear rotor pump, about 1/3 hp. These pumps move a lot of fuel and can run continuously. They will still pull thru a very dirty filter, and, they can be used to transfer fuel to or from another source, like a boat or truck.

 

[Capt Richard A.]

Have a similar setup on my 2 tanks. Fuel is drawn from the lowest point in the forward part of the tanks and returned with the engine fuel return at the furthest point in the rear.



Did this at the end of my 18 month refit process. Pump all the fuel into one tank, then back to the other, then repeat the process. There was still some residual crud that has come out in the filter, but the majority was picked up in the back and forth fuel polishing.

Ted

I used fuel stabilizer in the tanks to break it up a bit, before starting. Also. I changed the size of the pump so it was pretty powerfull going back in the tanks. I could see the difference with a flashlight looking in the inlet. But, like you said, you should run it through the tanks a couple time. I do.

 

[No Mast]

Per manufacturers recommendation when we use the fuel polisher, we set it to cycle the entire tanks volume 1.5 times. Also helpful to remember and shut off any cross feeds to other tanks while doing so.

 

[sunchaser]

Where do you guys get all this bad fuel that requires constant flow through a filter? Bahamas/neighboring islands and Mexico I can understand, dirty tanks that need emptying and a scrape out I can too, but normal NA stops let us know so we can avoid those stops.

 

[what_barnacles]

Old tanks are dirty tanks.

 

[No Mast]

Where do you guys get all this bad fuel that requires constant flow through a filter? Bahamas/neighboring islands and Mexico I can understand, dirty tanks that need emptying and a scrape out I can too, but normal NA stops let us know so we can avoid those stops.

I don't think thats generally it. We polish the fuel at the beginning of each season, then try to do it once every month or two. If we do take on fuel, we'll polish it. Its as easy as turning three valves and a switch on our boat. I look at it more as easy prevent maintenance than anything else. The big filter for the polisher sometimes gets clogged up after 5000 or 6000 gallons polishes, sometimes it lasts much longer. So thats all crud that would otherwise be building up inside the tank or could clog the primary filter when things are a bit bouncy.

 

[Russ Borman]

I'm planning on installing a polishing system as well, its not a lot of money and when things get dicey its not the time to say maybe I should have used one.

 

[Crusty Chief]

This is our system, 110ac. Very easy to use and with the timer it's a piece of cake. You do need to pay attention to draw and return but other than that pretty foolproof.

 

[O C Diver]

Where do you guys get all this bad fuel that requires constant flow through a filter? Bahamas/neighboring islands and Mexico I can understand, dirty tanks that need emptying and a scrape out I can too, but normal NA stops let us know so we can avoid those stops.

My boat probably moved 500 miles in the preceding 2 or 3 years before I purchased it. Most of that was moving it from Charleston, SC to Stuart, FL to the boat brokerage. Then I used it for 6 months and the fuel then sat for 18 months during my refit. I'm surprised there wasn't more gunk in the tanks.

Bad fuel isn't common, but it does happen. Fuel tank in my charter boat is spotless inside and draws from a sump. I consume 25 to 75% of the tank every trip, so there's a lot of fuel turn over. Got one bad load of fuel at the marina in Hatteras before heading home to Maryland. Separator filter on the Racor 1000 plugged on the next charter. The tanks at the Hatteras marina were old (since replaced). Probably took on fuel just after the tanker dropped a load in their tank, stirring the gunk up on the bottom of the marina's tank.

Bottom line, it happens. If you're carrying fuel around for months, better to polish the gunk out now that wait for a plugged separator.

Ted

 

[jleonard]

I installed a multi stage filtration system. I don't polish fuel.

 

[jjorgenson3]

Same here.

 

[Brooksie]

Me too. And the idea of leaving a fuel pump running while away from the boat scares the hell out of me.

IMHO Draw your fuel from the lowest point on the bottom of the tank (no dip tube almost to the bottom), decant the water off w/ a drip leg, filter it good, and forget the polishing.

 

[RNL]

I did the same thing with the multi-stage filtration system last summer on my boat. I have a polisher and have used it for years and have never picked up much debris. Don't know for sure if the fuel is just clean or more likely stuff on the bottom remains there. I feel more confidant with the multi-stage filtration set up. I also really appreciate the squeeze bulb for priming that I installed before the filters.

Glen

 

[Capt Richard A.]

I don't think thats generally it. We polish the fuel at the beginning of each season, then try to do it once every month or two. If we do take on fuel, we'll polish it. Its as easy as turning three valves and a switch on our boat. I look at it more as easy prevent maintenance than anything else. The big filter for the polisher sometimes gets clogged up after 5000 or 6000 gallons polishes, sometimes it lasts much longer. So thats all crud that would otherwise be building up inside the tank or could clog the primary filter when things are a bit bouncy.

That's right twice a year, never really concerned with that issue. USAF MI's. Just providing info.
It's like the old saying , your not a real Capt. Until you go aground.
Cheers

 

[Sharpseadog]

Is extra fuel polishing really needed?

I have been doing some fuel tank cleaning and was considering adding/making a fuel polishing system.
In doing so, I would like to use the lowest tank fitting where the valve is normally used for the fuel level sight tube. This will be the intake side to the fuel pump and filter. Then, the return side after the filter will be returned through the uppermost fitting where the top of the sight tube was. With 2 added valves, I can retain the sight tube.
Any problems in doing this?

I have a question. My Cummins QSB 5.9 typically runs between 2.5 and 6.0 GPH. It returns at least 20 GPH to the fuel tank. I have 2 - 200 gallon tanks. At 25 GPH going through the filters, the whole tank goes through the filter every 8 hours. Isn't that enough? What am I missing?

 

[sunchaser]

At 25 GPH going through the filters, the whole tank goes through the filter every 8 hours. Isn't that enough? What am I missing?

Don't see that you're missing anything. IMHO you understand the issue and concept very well.

Remember too, your vessel is reasonably new and fuel in your area quite good out of the dock nozzle. As vessels age, the opportunity for tanks gunking up increases, especially on lightly used vessels. Pulling a sample from the tank bottoms now and then is generally easy and probably wise.

 

[Crusty Chief]

Running the fuel through a polishing system or multiple filters (pretty much the same thing) is normally done when your not running your main or mains. At least that's what we do.
I like to think that by running the fuel from the tank through additional filters that are separate from your main fuel filters, will hopefully prevent the main filters from plugging up while running the main engine. That's the theory anyway.
Anything that you can do to keep the fuel as clean as possible can only help. As I mentioned above, if your running your main a lot, and burning up your fuel, the fuel dosent sit in the tanks long enough to grow stuff, assuming your tanks are clean in the first place.

 

[kulas44]

Most boat owners dont have a clue how dirty there tanks are. Mostly because they have never been in a situation that stirs up the crud. I have been ,done that, not fun. The problem being when you absolutely need it the most is when it happens, clogged filters, engine (s) shut down. Try changing filters, repriming, restarting, etc while your blowing towards the rocks. The pucker factor is very high. I choose to not do that again so I keep my fuel and tanks clean. My tanks all have access ports in every chamber and can be easily (sorta) inspected/cleaned. Circulating the fuel thru filters helps to keep the crud from settling on the tank bottom. I guess if you will never be in a situation that positively requires your engines to keep running for you, your passengers and the boats safety then polishing may be a waste of time.

 

[sunchaser]

Kulas

The assumption that all fuel polishing systems are good is not valid. As noted, how and where tanks are plumbed, volume recirculated, pipeline sizes and actual system performance remains a mystery to most. The various setups shown on TF are not all created equal. But, they do no harm so a balm is ok.