Simple Fuel Polishing

[Choices]

My boat does not have a fuel polishing set up, and burns fuel so slow I would like to add one.

Below is my layout in black. Red is what I would like to add for the polisher.

My plan is to use a Walbro 12v pump plumbed after a Raycor 500 with a vacuum gauge, that will keep spare parts easy.

There is a threaded port in the manifold, so I can nipple off of that and mount everything to the back of the manifold structure.

Each tank has a threaded tap at the top of the tank that is nipple blocked, that will be my return. I will always return fuel to the same isolated tank.

I think I can control where it goes and isolate each tank this way.

See any problems?

 

[Simi 60]

Look at how much fuel passes through your engine and back through return.
It may be more than the pump you use for polishing so simply using the boat for several hours could have the same effect.

 

[Choices]

I burn about 2 gal/ hr. Not much going back.

 

[bglad]

The polisher suction would typically draw from the supply manifold versus the return as you have drawn it. Seems like it would be tidier and just as flexible to draw from the supply manifold then send it back to the tanks via the return manifold. Install valves on the polisher connections to isolate it when your engines are running. This would allow you to choose which tank to polish and even transfer fuel if/when necessary and eliminate the need to add extra lines all the way to the tanks.

My boat does not have a fuel polishing set up, and burns fuel so slow I would like to add one.

Below is my layout in black. Red is what I would like to add for the polisher.

My plan is to use a Walbro 12v pump plumbed after a Raycor 500 with a vacuum gauge, that will keep spare parts easy.

There is a threaded port in the manifold, so I can nipple off of that and mount everything to the back of the manifold structure.

Each tank has a threaded tap at the top of the tank that is nipple blocked, that will be my return. I will always return fuel to the same isolated tank.

I think I can control where it goes and isolate each tank this way.

See any problems?

 

[Lepke]

It would be better to draw thru one of the Racor filters. They separate water better. You also need to add a conditioner when you fuel. A good one will slowly dissolve buildups in the tanks & lines and help the filter remove water. If you haven't used one in a long while, I'd suggest a 3x dose. I use a conditioner every fueling. And if fuel sits for more than 6 months, I add it again and circulate. While new fuel has stabilizer and biocides, it only lasts a few months. And new fuel is unstable, not formulated for good burning, stability, long storage, but clean, low sulfer burning. Many marinas don't have a high turnover but fill their tank for a better price. One near where I winter doesn't sell much diesel, and it can sit a couple years. I don't fuel there.
When I was a kid, diesel could sit for years.

 

[Liberty2015]

The polisher suction would typically draw from the supply manifold versus the return as you have drawn it. Seems like it would be tidier and just as flexible to draw from the supply manifold then send it back to the tanks via the return manifold. Install valves on the polisher connections to isolate it when your engines are running. This would allow you to choose which tank to polish and even transfer fuel if/when necessary and eliminate the need to add extra lines all the way to the tanks.

I agree with Bglads comments above, they are spot on and we just did the same a couple of weeks ago . We installed a Marco Diesel Transfer pump 24 volt , which moves 27 litres per minute , so moves quite a bit of fuel. Now we have that working fine off the manifolds, and can draw from any of our 6 tanks and return to any chosen one. We are researching a filter to place in line for polishing.

Cheers Chris D Liberty

 

[angus99]

Our system draws from the bottom of each tank (the blue hose is to equalize tank levels) and returns “polished” fuel to any tank via the return manifold.

(Look familiar, Bill?)

I’m a little concerned about the size of the return lines. I assumed they were all half-inch copper like the supply lines, but the returns are smaller. Not a problem for the meager amounts of fuel the Lehmans return but I’m hoping they’ll allow an adequate flow for the new higher-capacity polishing pump and filter I’m installing.

 

[JDCAVE]

This essay is worth reviewing. D’Antonio discusses the need for separate fuel pick up tubes for the system and proper plumbing.

https://stevedmarineconsulting.com/fuel-polishing-systems-explained/?upm_export=print